题库网 (tiku.one)

 找回密码
 立即注册

 

      

上传图片附件

未使用图片

小贴士: 允许的图片文件格式为: gif, jpg, jpeg, png, webp,上传完成后会在上方生成预览,用鼠标连续双击缩略图,或拖动缩略图,该图片就被绑定至本题,显示在题目下方

本次作答已使用

小贴士: 此栏目显示的是当前作答使用的所有图片,绑定到某一题目的图片同时会显示在该题目下方; 删除使用的图片会将其转移到<未使用图片>类别


习题练习:gc textbook chapter 8 Rotational Motion



 作者: admin   总分: 110分  得分: _____________

答题人: 匿名未登录  开始时间: 24年12月27日 14:40  切换到: 整卷模式

标记此题
1#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A bicycle odometer (which measures distance traveled) is attached near tsyf97kdf6ry *583g ttwmf:z fnm75rvhe wheel hub and is designed for 27-inch wheels. What happens if you use it on a bicycle with 24-inch wh3fk*y5 :fr 6f5 mg7zms8dtnyfvw rt79eels?
参考答案:    

标记此题
2#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Suppose a disk rotates at consta5o ag;jp( om87c(rqjr0gn- s.y mip,xnt angular velocity. Does a point on the rim have radial and/or tangential acceleration? If the disk’s angular velocity increases uniformly, does the point have radial and/or tangential acceleration? For which cases would the magnitude of either compjx5co7r;,no 0 -(g m .pgpsmqry ja8(ionent of linear acceleration change?
参考答案:    

标记此题
3#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Could a nonrigid body be described by a single value of the a)tj+xbl gav(t-*/t9+ f i 0rkjxwp5ax ngular velocity $\omega$ Explain.
参考答案:    

标记此题
4#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Can a small force ever exert a greater toreo,5*00vrbn 8n;, b c xpwqqgaque than a larger force? Explain.
参考答案:    

标记此题
5#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
If a force $\vec{F}$ acts on an object such that its lever arm is zero, does it have any effect on the object’s motion? Explain.
参考答案:    

标记此题
6#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Why is it more difficult to do a sit-up with your hands bm/. fd:ro4mf6.6uh umq jnjv 3ehind your head than when your arms are strd:3v6 r4num 6oufhm. mjf/ qj.etched out in front of you? A diagram may help you to answer this.
参考答案:    

标记此题
7#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A 21-speed bicycle hh5h9zk zgl/wseu9kz d4t 713vas seven sprockets at the rear wheel and three at the pedal craguszv7 wdz1 h4/h59z kkl 9e3tnks. In which gear is it harder to pedal, a small rear sprocket or a large rear sprocket? Why? In which gear is it harder to pedal, a small front sprocket or a large front sprocket? Why?
参考答案:    

标记此题
8#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Mammals that depend on being able to run fast fleae 2,yq1tl9t z(it/ 1njl1have slender lower legs with flesh and muscle concentrated high, close to the body (Fig. 8–34). On the basis o le2lqj1 z/eia1t(,ty 1nfl9tf rotational dynamics, explain why this distribution of mass is advantageous.
参考答案:    

标记此题
9#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Why do tightrope walkers (Fig. 8–35) carry w xlr9t;2(0r b.e nyc)ea0cro a long, narrow beam?
参考答案:    

标记此题
10#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
If the net force on a system z wdnchj :n;w/,u7+vr is zero, is the net torque also zero? If the net torque on a system n:7chnwj+, vrdu;zw/ is zero, is the net force zero?
参考答案:    

标记此题
11#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Two inclines have the same heif*/n 2euitlz klv8, 4ight but make different angles with the horizontal. The same steel ball is rolled down each incline. On which incline will the speed of the ball at the bottom be greate k24lzt*niluv 8 ief/,r? Explain.
参考答案:    

标记此题
12#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Two solid spheres simultaneously start rolling (bo i6.v4f): yagtc/byfrom rest) down an incline. One sphere has twice the radius and twice the mass of the other. Whai/o: gtybf y.b4c v)6ich reaches the bottom of the incline first? Which has the greater speed there? Which has the greater total kinetic energy at the bottom?
参考答案:    

标记此题
13#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A sphere and a cylinder have the( h8xlnvy7jj- same radius and the same mass. They start from rest at the top of an incline. Which reaches the bottom first? Which has the greater speed at the bottom? Which xjvl(j7y- n h8has the greater total kinetic energy at the bottom? Which has the greater rotational KE?
参考答案:    

标记此题
14#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
We claim that momentum and angular momentum are im6xm1juc)tbx)d8 ; uyq oti0 .i z)5oconserved. Yet most moving or rotating objects eventu om8x)m;y z ii6tc td 0.1uib)5)oqxujally slow down and stop. Explain.
参考答案:    

标记此题
15#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
If there were a great migration of people toward the Earth’s eq6,d yw-dz8 o00vwyl mzuator, how would this affect the length of the ddo mww, zv6y0-8dlzy0 ay?
参考答案:    

标记此题
16#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Can the diver of Fig. 8–29 do a somersault without having any initial rotatio:yy5 l)a) iwupjp d)8xfkt6-in when she leaves the boa- jw5f6 i) )l)yt xdp8kypui:ard?
参考答案:    

标记此题
17#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
The moment of inertia of a rotating solid disk about an axis through brqr *1 5v0 )9aiqgocpits center of mia g1vq59pro q0*brc)ass is $\frac{1}{2}WR^2$ (Fig. 8–21c). Suppose instead that the axis of rotation passes through a point on the edge of the disk. Will the moment of inertia be the same, larger, or smaller?
参考答案:    

标记此题
18#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Suppose you are sitting on a rotating stool holding a 2-kg mass in each outstre32p2i 6u k mzi9lx2zictched hand. If you suddenly drop tzim k2ciil22 uz3p6x9he masses, will your angular velocity increase, decrease, or stay the same? Explain.
参考答案:    

标记此题
19#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Two spheres look identical and have the same mass. However, one is hollow and thx2 8f g mb p0rn7oq.h82ccmbk017qox te other is solid. Describe an experiment to determine which o n.q72q0 rpb8k7 tg1x8fm0 xchomb2 cis which.
参考答案:    

标记此题
20#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
In whatdirection is the Earth’s angular velocity vector as it rotates daily about itsaxis?
参考答案:    

标记此题
21#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
The angular velocity of a wheel rotating on a horizontal axle points west. In whxz (zaxbw5 (p-( ikrredsi,4- at direction is the linear velocity of a point on the top of the wheel? If the angular acceleration points east, describe the tangential linear acceleration of this point at the top of the wheel. Is the aniearpw4b(x zsdkz , -r5ix( -(gular speed increasing or decreasing?
参考答案:    

标记此题
22#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Suppose you are standing on th5,xyj ;nyhfil)c u.l 2;o5zwuf yt:/ke edge of a large freely rotating turntable. What happens if you walk toward the fwuy kx:,n;l52u/i);5o jh cflyt z.ycenter?
参考答案:    

标记此题
23#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A shortstop may leap into the air to catch a ball and throw it quickly.1gxh 6ec b2mi7hv4g b; had+e5 As he throws the ball, the upper vec2xg;e hbg +da hmh7i15b64part of his body rotates. If you look quickly you will notice that his hips and legs rotate in the opposite direction (Fig. 8–36). Explain.
参考答案:    

标记此题
24#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
On the basis of the law of conservation of angupqtl9/d/-p +x iq;a prlar momentum, discuss why a helicopter r pal/p/q; q9pix+t- dmust have more than one rotor (or propeller). Discuss one or more ways the second propeller can operate to keep the helicopter stable.
参考答案:    

标记此题
25#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Express the following angles in radians: (a) 3b)s *w:f,tiqt0 $^{\circ} $, (b) 57 $^{\circ} $, (c) 90 $^{\circ} $, (d) 360 $^{\circ} $, and (e) 420 $^{\circ} $. Give as numerical values and as fractions of $\pi$.(Round to two decimal places)
(a)   $rad$ (b)   $rad$ (c)    $rad$ (d)    $rad$ (e)    $rad$

参考答案:     查看本题详细解析

标记此题
26#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Eclipses happen on Earth because of an amazing coincidence. Calculate, usio4z8tyq( h2gzac -9hkng the information inside the Front Cover, the angular diameters (in radians) of the Sun and the a48h z( k29 zg-tycoqhMoon, as seen on Earth.
Sun =    $rad$ Moon =    $rad$

参考答案:     查看本题详细解析

标记此题
27#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A laser beam is directed at the Moon, 380igd-:ky (k5ck *rqno . 8s0phkj( +hsi,000 km from Earth. The beam diverges at anic(sk. pyidkk(0h-j sh o g8 nr*k:+5q angle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon?    m



参考答案:     查看本题详细解析

标记此题
28#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The blades in a blender rotate at a rate of 6500 rpm. When the motor is turned k peph h5wctdt8y74mj 8+(h7eoff during operation, the blades slow to rest in 3.0 s. What is the angthd5p+ 8cew48 yekp t7jh m(h7ular acceleration as the blades slow down?    $rad/s^2$

参考答案:     查看本题详细解析

标记此题
29#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A child rolls a ball on a level floor 3.5 m to anoln o*bsq*8zz5 ther child. If the ball makes 15.oznsqb *l85 z*0 revolutions, what is its diameter?    m

参考答案:     查看本题详细解析

标记此题
30#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A bicycle with tires 68 cm in diameter travels 8.0 hko,x2zvv6 /o3yzl6*p, yvgamk f(bn1 s u2e5km. How many revolutions do the wheels make? lfz52ogoe*z1 6,k(/xvu3av, v ksh6py mn2by   $rev$

参考答案:     查看本题详细解析

标记此题
31#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  (a) A grinding wheel 0.bih1;m 0 x g2vueosxz. s;n/c8q+3fqb 35 m in diameter rotates at 2500 rpm. Calculate its angular velocitg h 8nifvz+1 3s. ;0u mo2qb/;xqcsebxy in $rad/s$ $\omega$ =    $rad/sec$
(b) What are the linear speed and acceleration of a point on the edge of the grinding wheel? v =    $m/s$ $a_R$ =    $ m/s^2$

参考答案:     查看本题详细解析

标记此题
32#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A rotating merry-go-rou / )qyh jp.q17qomje4pnd makes one complete revolution in 4.0 s (Fig. 8–38). (a) What is the linear speqq)pm1ey/4jqjpho 7.ed of a child seated 1.2 m from the center?    $m/s$
(b) What is her acceleration (give components)?    $m/s^2$    the center

参考答案:     查看本题详细解析

标记此题
33#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Calculate the angular velocity of the Earth (a) in its orbit)r0+akbut3 g7x:qoe wg:2t bd around the Sun    $ \times10^{-7 }$ $rad/s$
(b) about its axis.    $ \times10^{-5}$ $rad/s$

参考答案:     查看本题详细解析

标记此题
34#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the linear speed of a point xmi7;*n ; f-p;ugamfx
(a) on the equator,    $m/s$
(b) on the Arctic Circle (latitude 66.5$^{\circ} $ N),    $m/s$
(c) at a latitude of 45.0$^{\circ} $ N, due to the Earth’s rotation?    $m/s$

参考答案:     查看本题详细解析

标记此题
35#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How fast (in rpm) must a centrifuge rotate if a particle 7.0 cbnr a47-i+fn1 q csmj2m from the axis of rotation is to experience an acceleratisnfrjqcn1+a-4b2 m7i on of 100,000 $g’s$?    $rpm$

参考答案:     查看本题详细解析

标记此题
36#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 70-cm-diameter wheel aceh) foi b x7ulb-/7l vm9c4zx5celerates uniformly about its center from 130 rpm to 280 rpm in 4.0 s. u /i)c-5l bxxl9hboem74vz 7f Determine
(a) its angular acceleration,$\approx$    $rad/s^2$(Round to one decimal places)
(b) the radial and tangential components of the linear acceleration of a point on the edge of the wheel 2.0 s after it has started accelerating. $a_R$    $m/s^2$ $a_{tan}$    $m/s^2$

参考答案:     查看本题详细解析

标记此题
37#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A turntable of radiusjufl;/ls+o ab 3das4*4rg lf6 $R_1$ is turned by a circular rubber roller of radius $R_2$ in contact with it at their outer edges. What is the ratio of their angular velocities, $\omega_1$ / $\omega_2$
参考答案:    

标记此题
38#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In traveling to the Moon, astronauts aboluyu l;c0m2bk 8nk/ ;xard the Apollo spacecraft put themselves into a slow rotation to distribute the Sun’s energy evenly. At the start of their trip, they accelerated from no rotation to 1.0 revolution every2 /uk ul l;;k8yxm0cnb minute during a 12-min time interval. The spacecraft can be thought of as a cylinder with a diameter of 8.5 m. Determine
(a) the angular acceleration, $\approx$    $rad/s^2$
(b) the radial and tangential components of the linear acceleration of a point on the skin of the ship 5.0 min after it started this acceleration. $a_{tan}$ =    $ \times10^{ -4}$ $m/s^2$ $a_{rad}$ =    $ \times10^{ -3}$ $m/s^2$

参考答案:     查看本题详细解析

标记此题
39#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A centrifuge accelerates uniformly from rest to 15,000 rpm 4mkva/:nzds vq7fk/ 3;u 01i9frwcbvd 6gh+gin 220 s. Through how many revolutions did it turn in this tzdvnbigqvuh 3w+9kr g:f0 f 7am /v;1k4d/s6cime?    $rev$

参考答案:     查看本题详细解析

标记此题
40#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An automobile engine slows down from 4500 rpm to 120l.b-hyv0;)hd w k* vig0 rpm in 2.5 s. Calculate
(a) its angular acceleration, assumed constant,    $rad/s^2$
(b) the total number of revolutions the engine makes in this time.    $rev$

参考答案:     查看本题详细解析

标记此题
41#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Pilots can be tested for the stresses of flying highspeed jets in a whirling jc6v9 y6szh81y sk dtje0m8-v“human centrifuge,” which takes 1jcdk8j 6196vsv 0 y8 stmyze-h.0 min to turn through 20 complete revolutions before reaching its final speed.
(a) What was its angular acceleration (assumed constant),    $rev/min^2$
(b) what was its final angular speed in rpm?    $rpm$

参考答案:     查看本题详细解析

标记此题
42#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A wheel 33 cm in diameter accelerx d.iv7om.0if ates uniformly from 240 rpm to 360 rpm in 6.5 s. How far wilv. fio0xd 7.iml a point on the edge of the wheel have traveled in this time?    m

参考答案:     查看本题详细解析

标记此题
43#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A cooling fan is turned of9gu, rvxv 2s:db9cq(zg1avkal w 976 zf when it is running at 850rev/min It turns 1500 revolutions before it comes to a stq sbwvd2z,9xlaa9uv: k17(gc 69 r gvzop.
(a) What was the fan’s angular acceleration, assumed constant?    $\frac{rad}{s^2}$
(b) How long did it take the fan to come to a complete stop?    s

参考答案:     查看本题详细解析

标记此题
44#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The tires of a car make 65 revolutions as the car reduces its s3phv9y9or ,x+ (oboee xo/ a76fz,idmpeed uniformly from 95km/h to 45km/h The +e epfio v,a/rx9oo,73 m9hdo(by 6zx tires have a diameter of 0.80 m.
(a) What was the angular acceleration of the tires? $\approx$    $rad/s^2$
(b) If the car continues to decelerate at this rate, how much more time is required for it to stop?    s

参考答案:     查看本题详细解析

标记此题
45#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The tires of a car make 65 revolutions as the0hn1h ijybhv4 )n7z) r car reduces its speed uniformly from 95km/h to 45km/h Tv7hz)j) 1 nhiy0r4nh bhe tires have a diameter of 0.80 m.
(a) What was the angular acceleration of the tires? $\approx$    $rad/s^2$
(b) If the car continues to decelerate at this rate, how much more time is required for it to stop?    s

参考答案:     查看本题详细解析

标记此题
46#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 55-kg person riding a bike puts all her weight on each pedal when climv4p/f:cw9w;/vhe 2 v.an yqcsbing a hill. Thea4vn q chs9v.wc2e yw:vp/f /; pedals rotate in a circle of radius 17 cm.
(a) What is the maximum torque she exerts?    $m \cdot N$
(b) How could she exert more torque?

参考答案:     查看本题详细解析

标记此题
47#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A person exerts a force of 55 N on the end of a door 74 cm w9w+ hhwf -:5ly;aq xjvide. What is the magnitude of the torl-+hv9xww h;j5q y a:fque if the force is exerted
(a) perpendicular to the door    $m \cdot N$
(b) at a 45 $^{\circ} $ angle to the face of the door?    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
48#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Calculate the net torq vjz5u+.,drd6/0 qydw0pf wonue about the axle of the wheel shown in Fig. 8–39. Assume that a frindq0d+ our j,zpdwf/w5.0yv6 ction torque of 0.4 $m \cdot N$ opposes the motion.    $m \cdot N$  



参考答案:     查看本题详细解析

标记此题
49#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Two blocks, each of mass m, are attached to the ends of + 8p7ly5lnnzlt .r*qra massless rod which pivots as shown in Fig. 8–40. Initially the rod is held in the horizontal position and then released. Calculate the magnitude and direction of the net torque on this systemy8 lq+n.p5nz* tlr7rl.
参考答案:    

标记此题
50#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The bolts on the cylinder head of an engine da+jk7z i0z s:require tightening to a torque of 38dk +i:zaj 70sz $m \cdot N$ If a wrench is 28 cm long, what force perpendicular to the wrench must the mechanic exert at its end?    N
If the six-sided bolt head is 15 mm in diameter, estimate the force applied near each of the six points by a socket wrench (Fig. 8–41).    N


参考答案:     查看本题详细解析

标记此题
51#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Determine the moment of inertia of a 10.8-kg/t9b1e(9f xbq,g6;h pjrk h py sphere of radius 0.648 m when the axis of rotation is through its centeb/h9h(r xq6te g9pyp; b1f j,kr.    $kg \cdot m^2$

参考答案:     查看本题详细解析

标记此题
52#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Calculate the moment ofgl w(nu( qxe1z8zps9v o,2 bg. inertia of a bicycle wheel 66.7 cm in diameter. The rim and tire have a combined mas(ez. v8sx l ng b9ogu,(2pw1qzs of 1.25 kg. The mass of the hub can be ignored (why?).    $kg \cdot m^2$

参考答案:     查看本题详细解析

标记此题
53#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A small 650-gram ball on the end of a thin, light rod is rotated in a horizon(r-3b rx 7vbri1bs0c yw.6pqztal ci i y0s(w b6.r-317rpcvrxbzq brcle of radius 1.2 m. Calculate
(a) the moment of inertia of the ball about the center of the circle,    $kg \cdot m^2$
(b) the torque needed to keep the ball rotating at constant angular velocity if air resistance exerts a force of 0.020 N on the ball. Ignore the rod’s moment of inertia and air resistance.    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
54#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A potter is shaping a bowlzx1 3;xi4o7m pdcc1qs on a potter’s wheel rotating at constant angular speed (Fig. 8–4ic41o;xdc sq p71m x3z2). The friction force between her hands and the clay is 1.5 N total.
(a) How large is her torque on the wheel, if the diameter of the bowl is 12 cm?    $m \cdot N$
(b) How long would it take for the potter’s wheel to stop if the only torque acting on it is due to the potter’s hand? The initial angular velocity of the wheel is 1.6 rev/s, and the moment of inertia of the wheel and the bowl is 0.11 $kg \cdot m^2$.    s

参考答案:     查看本题详细解析

标记此题
55#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Calculate the moment of inertia of the array of point objectqcg-8l t7dcak+3o)o2qis 3 gis shown in Fig. 8–43 ab233ioac+8otqi k- l)dsqc gg7out
(a) the vertical axis,    $kg \cdot m^2$
(b) the horizontal axis. Assume m=1.8 kg,M=3.1kg and the objects are wired together by very light, rigid pieces of wire. The array is rectangular and is split through the middle by the horizontal axis.    $kg \cdot m^2$
(c) About which axis would it be harder to accelerate this array?



参考答案:     查看本题详细解析

标记此题
56#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An oxygen molecule consists of g flcm:7l*gpeaq/+h c pw /c)9two oxygen atoms whose total mass is $5.3 \times10^{ -26}$ kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is $ 1.9\times10^{-46 }$ $kg \cdot m^2$ From these data, estimate the effective distance between the atoms.    $\times10^{-10 }$ m

参考答案:     查看本题详细解析

标记此题
57#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  To get a flat, uniform cylindrical satellite spinning aw i 0qt*,ahei ;w-w1a7-ozfeot the correct rate, engineers fire four tangential rockets as shown in Fig. 8–44. If the satellite has a mass of 3600 kg and a radius of 4.0 m, what is the required steady force of each rocket if the satellite is to reach 32 rpm wht-,fe1w;o -q07*eizi aa woin 5.0 min? $\approx$    N(round to the nearest integer)


参考答案:     查看本题详细解析

标记此题
58#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A grinding wheel is a unii+q,. o1bjmi rform cylinder with a radius of 8.50 cm and a mass of 0.580 q,bm +1ori j.ikg. Calculate
(a) its moment of inertia about its center, $\approx$    $kg \cdot m^2$
(b) the applied torque needed to accelerate it from rest to 1500 rpm in 5.00 s if it is known to slow down from 1500 rpm to rest in 55.0 s。    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
59#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A softball player swings ay j*:igt l6z1dk6hq3x bat, accelerating it from rest to 3 $rev/s$ in a time of 0.20 s. Approximate the bat as a 2.2-kg uniform rod of length 0.95 m, and compute the torque the player applies to one end of it.    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
60#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A teenager pushes tangentially on a small hand-driven m /mnx.,ug0pg0x0no-jgwli 2 a erry-go-round and is able to accelerate it from rest to a frequency of 15 rpm in 10.0 s. Assume the merry-go-round is a uniform disk of radius 2.5 m and has a mass of 760 kg, and two children (each with a mass of 25 kg) sit opposite each other on the edig x0 mo-x.wa 2pgnujl/g0 ,0nge. Calculate the torque required to produce the acceleration, neglecting frictional torque. $\approx$   $m \cdot N$ What force is required at the edge?    N

参考答案:     查看本题详细解析

标记此题
61#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A centrifuge rotor rotating+6vc k f7-z;nxs5mpsfgpz+ t: at 10,300 rpm is shut off and is eventually brought uniformly to rest by a frictional tpz -; 5vfcmzns+ pk7gs +6tfx:orque of 1.2 $m \cdot N$ If the mass of the rotor is 4.80 kg and it can be approximated as a solid cylinder of radius 0.0710 m, through how many revolutions will the rotor turn before coming to rest,    $rev$ how long will it take?    s

参考答案:     查看本题详细解析

标记此题
62#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The forearm in Fig. 8–45 accelerates a 3.6qv-r+gkb1j+)g14 7 zaeqsv uc-kg ball at 7 $m/s^2$ by means of the triceps muscle, as shown. Calculate
(a) the torque needed,    $m \cdot N$
(b) the force that must be exerted by the triceps muscle. Ignore the mass of the arm.    N


参考答案:     查看本题详细解析

标记此题
63#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Assume that a 1.00-kg ball is thrown solely by the b yy0 4msjot6e f96br0tfn.3 (sq7tll action of the forearm, which rotates about the elbow joint under the action of the triceps muscle, Fig. 8–45. The ball is accelt nmt3t06(j9bf4 qy7y6 s f0 eloslrb.erated uniformly from rest to 10 $m/s$ in 0.350 s, at which point it is released. Calculate
(a) the angular acceleration of the arm,    $rad/s^2$
(b) the force required of the triceps muscle. Assume that the forearm has a mass of 3.70 kg and rotates like a uniform rod about an axis at its end.    N



参考答案:     查看本题详细解析

标记此题
64#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A helicopter rotor bladed vmi85 kl(3mfcj/kjvej7:i 2 can be considered a long thin rod, as shown in Fig. 8–4m jc:ikv i 3jved5f27/m(8jkl 6.
(a) If each of the three rotor helicopter blades is 3.75 m long and has a mass of 160 kg, calculate the moment of inertia of the three rotor blades about the axis of rotation.    $kg \cdot m^2$
(b) How much torque must the motor apply to bring the blades up to a speed of 5 $rev/s$ in 8.0 s?    $m \cdot N$


参考答案:     查看本题详细解析

标记此题
65#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
An Atwood’s machine consists of two massg. 9 rqqhh3n)qes, $m_1$ and $m_2$ which are connected by a massless inelastic cord that passes over a pulley, Fig. 8–47. If the pulley has radius R and moment of inertia I about its axle, determine the acceleration of the masses $m_1$ and $m_2$ and compare to the situation in which the moment of inertia of the pulley is ignored. [Hint: The tensions $F_{T1}$ and $F_{T2}$ are not equal. We discussed this situation in Example 4–13, assuming for the pulley.]

参考答案:    

标记此题
66#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A hammer thrower accelerates the hammer from rest within four fullr7 jmtkj1 p97y+q4 ae +e*fxq,afz4 qg turns (revolutions) and releq4q ff +aj1 7y,kza*m97rp t+xqgeje 4ases it at a speed of 28 $m/s$ Assuming a uniform rate of increase in angular velocity and a horizontal circular path of radius 1.20 m, calculate
(a) the angular acceleration,    $rad/s^2$
(b) the (linear) tangential acceleration,    $m/s^2$
(c) the centripetal acceleration just before release,    $m/s^2$
(d) the net force being exerted on the hammer by the athlete just before release,    N
(e) the angle of this force with respect to the radius of the circular motion.    $^{\circ} $

参考答案:     查看本题详细解析

标记此题
67#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A centrifuge rotor has a momnw + yilzzg451ent of inertia of $3.75 \times10^{-2 }$ $kg \cdot m^2$ How much energy is required to bring it from rest to 8250 rpm?    J

参考答案:     查看本题详细解析

标记此题
68#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An automobile engine develops a to *2yp w3lug;auco)a3tluu05 zrque of 280 $m \cdot N$ at 3800 rpm. What is the power in watts and in horsepower?    W    hp

参考答案:     查看本题详细解析

标记此题
69#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A bowling ball of mass 7.3 kg and radi(wh - j ;ysp;(hf*goutus 9.0 cm rolls without slipping down a lane j;g(- p*souhh(ywf; tat 3.3 $m/s$ Calculate its total kinetic energy.    J

参考答案:     查看本题详细解析

标记此题
70#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Estimate the kinetic energy of the Earth with resp6k n0xjs b9b1t7whl + hmb tf:6q6:lw2mlrzb*ect to the Sun as the sum of two te h f0nsm jrbq: w+tkblmzt6b62*76x1h9wllb :rms,
(a) that due to its daily rotation about its axis,$KE_{daily}$=    $\times10^{29 }$ J
(b) that due to its yearly revolution about the Sun. $KE_{yearly}$+    $\times10^{33 }$ J [Assume the Earth is a uniform sphere with $6 \times10^{ 24}$ kg and $6.4 \times10^{6 }$ m and is $1.5 \times10^{8 }$ km from the Sun.]$KE_{daily}$ + $KE_{yearly}$ =    $ \times10^{33 }$ J

参考答案:     查看本题详细解析

标记此题
71#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A merry-go-round has a mass of 16*jicemdnq:,6 s qu-6 k7g lpaocc(8d340 kg and a radius of 7.50 m. How much net work is required to acceleratq(uil6acdk p8-j7*:ogc s3q,6 ce md ne it from rest to a rotation rate of 1.00 revolution per 8.00 s? Assume it is a solid cylinder.    J

参考答案:     查看本题详细解析

标记此题
72#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sphere of radius 20.0 cm and mass 1.80 kg ayp;ec8k(o /q tr(b7 ostarts from rest and rolls without slipping downyokt(o7ca;q( /erp8 b a 30.0 $^{\circ} $ incline that is 10.0 m long.
(a) Calculate its translational and rotational speeds when it reaches the bottom. $v_{CM}$ =    $\omega$ =    $rad/s$
(b) What is the ratio of translational to rotational KE at the bottom?    Avoid putting in numbers until the end so you can answer:
(c) do your answers in (a) and (b) depend on the radius of the sphere or its mass?

参考答案:     查看本题详细解析

标记此题
73#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two masses, $m_1$ = 18 kg and $m_2$ = 26.5 kg are connected by a rope that hangs over a pulley (as in Fig. 8–47). The pulley is a uniform cylinder of radius 0.260 m and mass 7.50 kg. Initially, is on the ground and $m_2$ rests 3.00 m above the ground. If the system is now released, use conservation of energy to determine the speed of $m_2$ just before it strikes the ground. Assume the pulley is frictionless.    $m/s$


参考答案:     查看本题详细解析

标记此题
74#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 2.30-m-long pole is balanced vertically on its tip. It starts to fall and its m ehy y vnxbv75(*6:aflower end does not slip. What will be the speed of the upper end of the pole just before it hits the ground? [Hint: Use conservation oy a e(hv:*6 5f7vmyxbnf energy.]    $m/s$

参考答案:     查看本题详细解析

标记此题
75#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the angular momentum of a 0.210-kg ball rotat1 zjp g7p; )dzq,zira9ing on the end of a thin string in a circl,zd9p 1ag);zp7 jrzqie of radius 1.10 m at an angular speed of 10.4 $rad/s$?    $kg \cdot m^2$

参考答案:     查看本题详细解析

标记此题
76#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  (a) What is the angular momentum of a 2.8-kg unlk(kz d9g-sw4f69tam,a n y7hc iq*3jiform cylindrical grinding wheel of radius 18 cm when rotating at 1500 r9(9t c4z6dwilaa - fqmsgjh*7,3k nykpm?    $kg \cdot m^2$
(b) How much torque is required to stop it in 6.0 s?    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
77#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A person stands, hands at his side, on a platform that is rotating att;xe.;pc)mt-k x+lxt 1f htdk5t. )+ji6snhj a rate of 1.3rev/s If he raises his arms to a horizontal position, Fig. 8–48, thee;;ti.t xt .jn f+kk jx5ts )x+mhchd- )l6tp1 speed of rotation decreases to 0.8 $rev/s$ (a) Why?
(b) By what factor has his moment of inertia changed?

参考答案:    

标记此题
78#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A diver (such as the one shown in Fig. 8–29) /hny*; *bqx )t yze6kxs(y jjbi18f s4can reduce her moment of inertia by a factor of about 3.5 when changinjjybk 1stexx(ifsh;y*)n8 / 6b*qz y4g from the straight position to the tuck position. If she makes 2.0 rotations in 1.5 s when in the tuck position, what is her angular speed ($rev/s$) when in the straight position?   $rev/s$


参考答案:     查看本题详细解析

标记此题
79#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A figure skater can increase her spin rot +yhkpeje)9p 7ation rate from an initial rate of 1.0 rev every 2.0 s toe7phk+y )ej 9p a final rate of 3 $rev/s$ If her initial moment of inertia was 4.6 kg*$m^2$ what is her final moment of inertia? How does she physically accomplish this change?    $kg \cdot m^2$

参考答案:     查看本题详细解析

标记此题
80#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A potter’s wheel is rotating around a vertical ax+4b xo7 hdu4fiis through its center at a frequen4xu4hfboi + 7dcy of 1.5rev/s The wheel can be considered a uniform disk of mass 5.0 kg and diameter 0.40 m. The potter then throws a 3.1-kg chunk of clay, approximately shaped as a flat disk of radius 8.0 cm, onto the center of the rotating wheel. What is the frequency of the wheel after the clay sticks to it?    $rev/s$

参考答案:     查看本题详细解析

标记此题
81#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  (a) What is the angular momentum of a figure skater spinning fu viy,*dg;3t80 ftyf at 3.5 $rev/s$ with arms in close to her body, assuming her to be a uniform cylinder with a height of 1.5 m, a radius of 15 cm, and a mass of 55 kg?    $kg \cdot m^2$
(b) How much torque is required to slow her to a stop in 5.0 s, assuming she does not move her arms?    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
82#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Determine the angular mome)l jerr, t9)a-u rpfc o-*,rlxntum of the Earth
(a) about its rotation axis (assume the Earth is a uniform sphere),    $\times 10^{33} \; kg \cdot m^2$

(b) in its orbit around the Sun (treat the Earth as a particle orbiting the Sun). The Earth has mass $6 \times 10^{24} \; kg$ and radius $6.4 \times 10^{6} \; m$ and is $1.5 \times 10^{8} \; km$ from the Sun.    $\times10^{40} \; kg \cdot m^2$

参考答案:     查看本题详细解析

标记此题
83#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A nonrotating cylindrical disk of moment o8wapt qy iwtwcd kr+. 43s7+h3f inertia I is dropped onto an identical disk rotating at a y qc+w.swt 8ak3hi +wdtp347rngular speed $\omega$ Assuming no external torques, what is the final common angular speed of the two disks?
参考答案:    

标记此题
84#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A uniform disk turns at 2) msmo9we g*hmi i18ja3 cbf7 qt)3jd:.4 $rev/s$ around a frictionless spindle. A nonrotating rod, of the same mass as the disk and length equal to the disk’s diameter, is dropped onto the freely spinning disk, Fig. 8–49. They then both turn around the spindle with their centers superposed. What is the angular frequency in rev/s of the combination?    $rev/s$


参考答案:     查看本题详细解析

标记此题
85#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A person of mass 75 kg stands at the center of a rotating merry-go-mf*n9w6 :9avl z+vij5lvn cj/ round platform of radius 3.0 m and moment of inertia 920 +:/ 5lzmf 9wvjvv9n ajnc6*li$kg \cdot m^2$ The platform rotates without friction with angular velocity 2 $rad/s$ The person walks radially to the edge of the platform.
(a) Calculate the angular velocity when the person reaches the edge.    $rad/s$
(b) Calculate the rotational kinetic energy of the system of platform plus person before and after the person’s walk.$KE_i$ =    J $KE_f$ =    J

参考答案:     查看本题详细解析

标记此题
86#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 4.2-m-diameter merry-go-round (1y -av bfo8-lcl s7q2ssfu;vis rotating freely with an angular velocity of 0.828-sylo7b;aqlusf -csf1v(v $rad/s$ Its total moment of inertia is 1760 $kg \cdot m^2$ Four people standing on the ground, each of mass 65 kg, suddenly step onto the edge of the merry-go-round. What is the angular velocity of the merry-go-round now?    $rad/s$ What if the people were on it initially and then jumped off in a radial direction (relative to the merry-go-round)?    $rad/s$

参考答案:     查看本题详细解析

标记此题
87#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose our Sun eventually collapses into a white dw( 1n;dd- yohk/9 if;akwg1v wbarf, losing about half its mass in the process, and winding up with a radiuwkg1df ;h 1 bw9-n (voa/k;dyis 1.0% of its existing radius. Assuming the lost mass carries away no angular momentum, what would the Sun’s new rotation rate be?(round to the nearest integer)$\approx$    $rad/s$ (Take the Sun’s current period to be about 30 days.) What would be its final KE in terms of its initial KE of today?$KE_{f}$=    $KE_{i}$

参考答案:     查看本题详细解析

标记此题
88#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Hurricanes can involve winds in excessq96 h0to 4zf5rceh-qr a 4q)gm of 120 $km/h$ at the outer edge. Make a crude estimate of
(a) the energy,    $ \times10^{16 }$ J
(b) the angular momentum, of such a hurricane, approximating it as a rigidly rotating uniform cylinder of air (density 1.3 $kg \cdot m^2$) of radius 100 km and height 4.0 km.    $ \times10^{20 }$ $kg \cdot m^2$

参考答案:     查看本题详细解析

标记此题
89#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An asteroid of mass sd mm5fmuzw/( )--ep a$ 1.0\times10^{ 5}$ traveling at a speed of relative to the Earth, hits the Earth at the equator tangentially, and in the direction of Earth’s rotation. Use angular momentum to estimate the percent change in the angular speed of the Earth as a result of the collision.    $\times10^{-16 }$ %

参考答案:     查看本题详细解析

标记此题
90#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A person stands on a platform, initiakk4z o*z2bxy yi98)h+, aebtblly at rest, that can rotate freely without friction. The moment of inertia of the person plus the plaokh9y t*+ak,b2)x eb 8yz4zbi tform is $I_P$ The person holds a spinning bicycle wheel with its axis horizontal. The wheel has moment of inertia $I_W$ and angular velocity $\omega_W$ What will be the angular velocity $\omega_W$ of the platform if the person moves the axis of the wheel so that it points (a) vertically upward, (b) at a 60º angle to the vertical, (c) vertically downward? (d) What will $\omega_P$ be if the person reaches up and stops the wheel in part (a)?
参考答案:    

标记此题
91#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose a 55-kg person stands at gwt zxu9 u5p2)the edge of a 6.5-m diameter merry-go-round turntable that is mounted on fwup gxz9 t2)5urictionless bearings and has a moment of inertia of 1700 $kg \cdot m^2$ The turntable is at rest initially, but when the person begins running at a speed of 3.8 $m/s$ (with respect to the turntable) around its edge, the turntable begins to rotate in the opposite direction. Calculate the angular velocity of the turntable.    $rad/s$

参考答案:     查看本题详细解析

标记此题
92#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A large spool of rope rolls on the groun4h668x1aesznl a vs4 qd with the end of the rope lying on the top edge of the spool. A person grabs the end of the rope and walks a distance L, holding onto it, Fig. 8–50. The spool rolls behind the person without slipping. What length of rope unwinds from the spool? How far does the spool’vaql h466sxs8 a1 ze4ns center of mass move?
参考答案:    

标记此题
93#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The Moon orbits the Earth such that the same side always face aa6e-m.:; xi ivuimt*s the Earth. Determine the ratio of thee-x amut*i. :ma iv;i6 Moon’s spin angular momentum (about its own axis) to its orbital angular momentum. (In the latter case, treat the Moon as a particle orbiting the Earth.)    $\times10^{ -6}$

参考答案:     查看本题详细解析

标记此题
94#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A cyclist accelerates from rest at a rate of 1 mzp;s/2 lwnk +mpc6:t o/$s^2$ How fast will a point on the rim of the tire at the top be moving after 3.0 s? [Hint: At any moment, the lowest point on the tire is in contact with the ground and is at rest — see Fig. 8–51.]    $m/s$


参考答案:     查看本题详细解析

标记此题
95#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1.4-kg grindstone in the shape of a uniform cylinder of radius 0.20 m acqubbx s.z4x.1juc1n l ;b 55yyszires a rotatioz1sylzx455 b.; .xyus jbcbn1 nal rate of from rest over a 6.0-s interval at constant angular acceleration. Calculate the torque delivered by the motor.    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
96#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  (a) A yo-yo is made of two solid cylinwyjz r8: kzb7*drical disks, each of mass 0.050 kg and diameter 0.075 m, joined by a (concentric) thin solid 8j zkwbyz7:* rcylindrical hub of mass 0.0050 kg and diameter 0.010 m. Use conservation of energy to calculate the linear speed of the yo-yo when it reaches the end of its 1.0-m-long string, if it is released from rest.    $m/s$
(b) What fraction of its kinetic energy is rotational?    %

参考答案:     查看本题详细解析

标记此题
97#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  (a) For a bicycle, how is the angular speed of the rear wc x)3zvejai-:w);xtd heel ($\omega_R$) related to that of the pedals and front sprocket ($\omega_F$) Fig. 8–52? That is, derive a formula for ($\omega_R$)/($\omega_F$) Let $N_F$ and $N_R$ be the number of teeth on the front and rear sprockets, respectively. The teeth are spaced equally on all sprockets so that the chain meshes properly.
(b) Evaluate the ratio ($\omega_R$)/($\omega_F$) when the front and rear sprockets have 52 and 13 teeth, respectively,   
(c) when they have 42 and 28 teeth.   


参考答案:     查看本题详细解析

标记此题
98#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose a star the size jpzb (*ir3x1jof our Sun, but with mass 8.0 times as great, were rotating at a speed of 1.0 revolution every 12 days. If it z r13p(xbj* jiwere to undergo gravitational collapse to a neutron star of radius 11 km, losing three-quarters of its mass in the process, what would its rotation speed be? Assume that the star is a uniform sphere at all times, and that the lost mass carries off no angular momentum.    $\times10^{9 }$ $rev/day$

参考答案:     查看本题详细解析

标记此题
99#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  One possibility for a low-pollution automobile is for it to use energ4p 5kdtd4hyp1 y stored in a heavy rotating flywheel. Suppose such a car has a total mass of 1400 kg, uses a ut5hkp p1dy4d4 niform cylindrical flywheel of diameter 1.50 m and mass 240 kg, and should be able to travel 350 km without needing a flywheel “spinup.”
(a) Make reasonable assumptions (average frictional retarding force = 450N twenty acceleration periods from rest to equal uphill and downhill, and that energy can be put back into the flywheel as the car goes downhill), and show that the total energy needed to be stored in the flywheel is about $ 1.7\times10^{8 }$J.    $ \times10^{ 8}$ J
(b) What is the angular velocity of the flywheel when it has a full “energy charge”?    $rad/s$
(c) About how long would it take a 150-hp motor to give the flywheel a full energy charge before a trip? $\approx$    min

参考答案:     查看本题详细解析

标记此题
100#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Figure 8–53 illustrates(6ck5 kzoshx wbq sh+ n9bib)5076h ow an $H_2O$ molecule. The O–H bond length is 0.96 nm and the H–O–H bonds make an angle of 104 $^{\circ} $. Calculate the moment of inertia for the $H_2O$ molecule about an axis passing through the center of the oxygen atom
(a) perpendicular to the plane of the molecule,    $\times10^{-45 }$ $kg \cdot m^2$
(b) in the plane of the molecule, bisecting the H–O–H bonds.    $ \times10^{-45 }$ $kg \cdot m^2$


参考答案:     查看本题详细解析

标记此题
101#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A hollow cylinder (hoopf(utbf n-ys 57) is rolling on a horizontal surface at speed v=3.3 $m/s$ when it reaches a 15 $^{\circ} $ incline.
(a) How far up the incline will it go? $\approx$    m (round to one decimal place)
(b) How long will it be on the incline before it arrives back at the bottom?    s

参考答案:     查看本题详细解析

标记此题
102#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A uniform rod of mass M and length L can pivot frk m8xho -it4l)7qwg y.ui:+c feely (i.e., we ignore friction) about a hinge attached to a wall, as in Fig. 8–54. The rod is held horizontally and then released. At the moment of release, determine (a) the angular acceleration of the rod, and (b) the linear acceleration of the tip of the rod. Assume that the forcef.yi to xwm7c4)+kliu8 q hg:- of gravity acts at the center of mass of the rod, as shown. [Hint: See Fig. 8–21g.]

参考答案:    

标记此题
103#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A wheel of mass M has rale snfyy,b)n2)siwb9*s y h*:dius R. It is standing vertically on the floor, and we want to exeb9 yn))yh yi slwns*:s be2*,frt a horizontal force F at its axle so that it will climb a step against which it rests (Fig. 8–55). The step has height h, where h

参考答案:    

标记此题
104#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A bicyclist traveling with speed v=4.2m/s on a flat road is making a turgy.oc 3 nh,ky;n with a n.yh,yk3 gc o;radius The forces acting on the cyclist and cycle are the normal force $\left(\mathbf{\vec{F}}_{\mathrm{N}}\right)$ and friction force $\left(\mathbf{\vec{F}}_{\mathbf{fr}}\right)$ exerted by the road on the tires, and $m\vec{\mathbf{g}}$ the total weight of the cyclist and cycle (see Fig. 8–56).
(a) Explain carefully why the angle $\theta$ the bicycle makes with the vertical (Fig. 8–56) must be given by tan $\tan\theta=F_{\mathrm{fr}}/F_{\mathrm{N}}$ if the cyclist is to maintain balance.(round to the nearest integer)
(b) Calculate $\theta$ for the values given.    $^{\circ} $
(c) If the coefficient of static friction between tires and road is $\mu_s=0.70$ what is the minimum turning radius?    m



参考答案:     查看本题详细解析

标记此题
105#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose David puts a 0.50-kg rlh/jhck o.oeq45 8b ojqq9h-2ock into a sling of length 1.5 m and begins whirling the rock in a nearly horizontal circle above his head, accelerating it from rest to a rch b2lq/ h ehq.q -jo59jko8o4ate of 120 rpm after 5.0 s. What is the torque required to achieve this feat, and where does the torque come from?    $m \cdot N$

参考答案:     查看本题详细解析

标记此题
106#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Model a figure skater’s body as a solid cylinder and j m+o y8 thiek,*4q(8atzq1dlher arms as thin rods, making reasonable estimates for the dimensions. Then calculate qqt+lj8*4 hmk(,yda8o zi1te the ratio of the angular speeds for a spinning skater with outstretched arms, and with arms held tightly against her body.   

参考答案:     查看本题详细解析

标记此题
107#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You are designing a clutch as, i3ptzj9p iu3sembly which consists of two cylindrical plates, of mass3iu9tp jz3p i, $M_{\mathrm{A}}=6.0$ $\mathrm{kg}$ and $M_{\mathrm{B}}=9.0$ $\mathrm{kg}$ with equal radii R=0.60 $\mathrm{m}$ They are initially separated (Fig. 8–57). Plate $M_{\mathrm{A}}$ is accelerated from rest to an angular velocity $\omega_1=7.2$ $\mathrm{rad/s}$ in time $\Delta t=2.0$ s Calculate
(a) the angular momentum of $M_{\mathrm{A}}$    $kg \cdot m^2$
(b) the torque required to have accelerated $M_{\mathrm{A}}$ from rest to $\omega_{1}$    $m \cdot N$
(c) Plate $M_{\mathrm{B}}$ initially at rest but free to rotate without friction, is allowed to fall vertically (or pushed by a spring), so it is in firm contact with plate $M_{\mathrm{A}}$ (their contact surfaces are high-friction). Before contact, $M_{\mathrm{A}}$ was rotating at constant $\omega_{1}$ After contact, at what constant angular velocity $\omega_{s}$ do the two plates rotate?    $rad/s$


参考答案:     查看本题详细解析

标记此题
108#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A marble of mass m and radius r rolls adh5)f+ :i/ hp-.mwbzbf fasj2 long the looped rough track of Fig. 8–58. What is the minimum value of the vertical height h that the marble must drop if it is to reach the hif)m bj2f+a:fw/ hiz5b-d.shp ghest point of the loop without leaving the track? Assume $r\ll R$ and ignore frictional losses. h =    R



参考答案:     查看本题详细解析

标记此题
109#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Repeat Problem 84, but do not assum0 nc9w by/o;-ebcs zu jti0ato3*1dx 5e $r\ll R$ h =    (R-r)

参考答案:     查看本题详细解析

标记此题
110#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The tires of a car make 85 rev s9t( zm8-wv8 bmvp.tluqhyh8v*h4 a6olutions as the car reduces its speed uniformly frpm8 9th( 4vq8uyv.w tmvs6zhhb 8a*l- om 90km/h to 60km/h The tires have a diameter of 0.90 m. (a) What was the angular acceleration of each tire? $\approx$    $rad/s^2$(round to two decimal place)
(b) If the car continues to decelerate at this rate, how much more time is required for it to stop?    s

参考答案:     查看本题详细解析

  • :
  • 总分:110分 及格:66分 时间:不限时
    未答题: 已答题:0 答错题:
    当前第 题,此次习题练习共有 110 道题
    本系统支持习题练习,作业与考试三大模式,作业考试自动评分,成绩排序一键导出,可设定动态变量同一试卷千人千题
    如果您对本系统感兴趣,想加入我们或者想进行任何形式的合作,请加微信 skysky1258

    浏览记录|手机版首页|使用帮助|题库网 (https://tiku.one)

    GMT+8, 2025-7-23 19:03 , Processed in 0.348681 second(s), 242 queries , Redis On.