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 physics textbook chapter 6 problems



 作者: admin   总分: 119分  得分: _____________

答题人: 匿名未登录  开始时间: 12月08日 20:28  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  
In what ways is the word “work” as used in everyday language the same ac4h ei*3 vtr9wrm/ ck.s that defined in physics? In what ways is it different? Give examples of bothhr/ 9w3* mvte cckri4..
参考答案:     查看本题详细解析

标记此题
2#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Can a centripetal force ever do work on an object? Exp5le1,4- o6 )oy ymms1owqi0kikus c.x lain.
参考答案:     查看本题详细解析

标记此题
3#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Can the normal force on an object ever do wop tq qqiomk.c2y-bel t53.qg0- w9oq+ rk? 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  
A woman swimming upstream is not movie1mvggt +m7 lu0yhfppq0oh/y 7)t e7,ng with respect to the shore. Is she doing any work? If she stops swimming and merely floats, is woh vm/7g7u+p70fyh, l)pg tqmy0oe 1et rk done on her?
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  
Is the work done by kinetic friction forces always negative? [Hint: Consider wha;t;qd fw40,e/ur5a)j jtbusu t happens to the dishes when you pull a tabsjf5a 4, e wq)0j;t u/uturb;dlecloth out from under them.]
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 tiring to push hard against a solid wall even though you are doing+;aamd a2x0b m no woamb0d +2a; amxrk?
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  
You have two springsacfm kzo.l;)j ,9:niq that are identical except that spring l is stiffer than spring 2 j:zi m 9lf an.;,k)qoc$(k_1>k_2).$ On which spring
is more work done $(a)$ if they are stretched using the same force, $(b)$ if they are stretched the same distance?
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  
A hand exerts a constant horizontal force on a block that is free to slide onvel9+emvr;jr5.s o4by 6ml 7hz* kb)k a frictionless surface (Fig.6-30). The block starts from rest at þoint A, and by the time it has traveled aryv k+9sb6be )m4j .5oe;lvl*mrhzk 7 distance $d$ to point B it is traveling withe bint $o$ point B it is traveling with speed $\nu_\mathrm{B}$.When the block has traveled another distance $d$ to point C, will its speed be greater than, less than, or equal to 2$\nu_\mathrm{B}$? Explain your reasoning

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  
By approximately how much does your gravitation(br l;kaq1 1ab- 7 cn,ti1tnnhal potential energy change when you jump as l(r1 a1cki; qtn nb1th-,n7bahigh as you can?
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  
In Fig. 6–31, water moj smm,5/w fw+a. moqh2x e43balloons are tossed from the roof of a building, all with the same speed but with different launch angles. Which one has the highest speed on impact? Ign/3q m,of5hwom.e+ j4 2mwsx maore air resistance.


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  
A pendulum is launched from a point thatiejc3-fr,j:x i eq5ndm0 3aw;wcx9b; is a height h above its lowest point in two different ways (Fig. 6–32). During both launches, the pendulum is given an initial speed of 3.0m/s On the first launch, the initial ve-5xe iq;n03mcebjaxwcw fr,j 9d :3 i;locity of the pendulum is directed upward along the trajectory, and on the second launch it is directed downward along the trajectory. Which launch will cause it to swing the largest angle from the equilibrium position? 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  
A coil spring of mass m rests upright on a tg0dil*kra 3 6gable. If you compress the spring by pressing down with your hand and then release it, can the spring leave the table?d3g ki0l*g6a r Explain, using the law of conservation of energy.
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 bowling ball is hung from tj/5oy0fc* 1 iplycz.dhe ceiling by a steel wire (Fig. 6–33). The instructor pulls the ball back and stands against the wall with the ball against his nose. To avoid injury the instructor is supposed to o plj5.cz yy/*d01cif release the ball without pushing it. Why?

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  
What happens to the gravitational potential energy when water at the top o3 lue .;fiqr)5/ mucdxf a waterfaluq3).mexfc5iu/ r l; dl falls to the pool below?
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  
Describe the energy transformations when a cb xkf2hhg,l)8p l3+i;u8bh d fhild hops around on a pogo stick.
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  
Describe the energy tra2v t,p,8)8t2jeg ipchw5, spho j d1zvnsformations that take place when a skier starts skiing down a hill, but after a thwo s , pp81hcpj)v 2,ig25,dev 8tzjtime is brought to rest by striking a snowdrift.
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  
A child on a sled (total mass m) starts from rest at the top of a hi0x (*o)bw -jgnq.o ,ygc fvp8ell of height h and slj*8y)ggqc(.f onex- o0vbwp,ides down. Does the velocity at the bottom depend on the angle of the hill if (a) it is icy and there is no friction, and (b) there is friction (deep snow)?
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  
Seasoned hikers prefer to step over a fallen log in their path rather than stvkvcv9xi.;o f :5gvd- epping on top and jumping down on the other svoig: x vvv ;.9c-5kdfide. 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 identical arrows, one with twice the speed of the other, are fired into a b-hdcvac) lw (l i*5*wxale of hay. Assuming the hay exeid c*lhxw *l)(5awc- vrts a constant frictional force on the arrows, the faster arrow will penetrate how much farther than the slower arrow? Explain.
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  
Analyze the motion of a simple swinging pendulum iy z0pvw9y ;i 1kb0dc1jn terms of energy, (a) ignoring friction, and (b) taking friction into account. Explain why a grandfather clock has to be wound ydvc901yi0z pb ;k1jwup.
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  
When a “superball” is dropped, can it rebound to a height greater 83tfma: qp7ps 8vqk *dthan its original heightpmq*8dqs783 vkpf :at? Explain.
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 lift a suitcase from the floor to a table. The work you do onm* z3fqvc+r9 -w twwcm-vgt ,ix+f(-x the suitcase depends on which of the following: (a) whether you lift it straight up or along a more complicated path, (b) the time it takes, (c) thev-cw+( m9 xwfc,+* 3wgmzqtf-i-tx vr height of the table, and (d) the weight of the suitcase?
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  
Repeat Question 22 for the p- 9p1qdx2j iv y-9pyeeower needed rather than the work.
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  
Why is it easier to climb a mountain via a zigzag trail than to climb straik5:tu:.oj+-ps nstcs ght uptn ps+o:tsj k.5s:c-u?
参考答案:    

标记此题
25#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
Recall from Chapter 4, Example 4–14, that you can use a pulley and ropes to decr-)1( e-vcr h8uxb pawoease the force needed to raise a heavy load (see Fig. 6–34). But for every meter the load is raised, how much rope must be pulled u - cu1-wxpo8ehr(b)va p? Account for this, using energy concepts.
参考答案:    

标记此题
26#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How much work is done by the gravitational force when a 265-kg pile driver f wm) xyyof))tbde);3+u : gckxalls 2.80 m?od+) x xc3):gybmk;w)tfy) eu    J

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 65.0-kg firefighter climbs a f.aq,1 c4 j;: bmertjrusg u5c5light of stairs 20.0 m high. How much work is requirucqb;5.:rm5teas juj1c4r , g ed?    J

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  
  A 1300-N crate rests on the floor ,5z.mmfx0h :0))llu +mnxeg nltmy,k 7ndk.f . How much work is required to move it at constant speed (a) 4.0 m alongm7m..ey:fkuz k )t0l)0ldg hmlnn+,fmx , xn5 the floor against a friction force of 230 N,    J
(b) 4.0 m vertically?    J

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  
  (I) How much work did/p 2ay3 u hm3/yvim+ (dncgll8 the movers do (horizontally) pushing a 160-kg crate 10.3 m across a rough floor without acceleration, if the effective coefficient o3v//3ygl(nma82 dlum+c y h pif friction was 0.50?    J

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 box of mass 5.0 kg is accelerated by a fo u5a ,8jx h p1xikz66kex+mdp,rce across a floor at a rate of for 7.0 s. Find the net work done ,hxmd6k 18z6p ,5+ue kjaxp ixon the box.   J

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  
  Eight books, each 4.3 c cuvxe**e+gk l;tbn(8/z*b ng qtj2 6dm thick with mass 1.7 kg, lie flat on a table. How much work is required to stack t teq*bg*n/ ;v x8dbj6(ge2ztnu kl +*chem one on top of another?    J

参考答案:     查看本题详细解析

标记此题
32#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A lever such as that shown in Fig. 6-35 candvmj: hndd4mtf0 (2-o be used to liff objects we might not otherwise be able to liff. Show that the ratio of output force, f hmtvd4(-0d mnd o:j2$F_{\mathrm{O}}$, to input force, $F_{\mathrm{I}}$, is related to the lengths $\iota_\mathrm{I}$ and $\iota_\mathrm{o}$ from the pivot point by $F_{\mathrm{O}}/F_{\mathrm{I}}=l_{\mathrm{I}}/l_{\mathrm{O}}$ (ignoring friction and the mass of the lever), given that the work output equals work input.
参考答案:    

标记此题
33#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 330-kg piano slides 3.6 m do2j, 2ol.6del bfc 0xefwn a 28° incline and is kept from accelerating by a man who is pushineobf2 .cfld,e2j6 lx0 g back on it parallel to the incline (Fig. 6-36). The effective coefficient of kinetic friction is 0.40. Calculate:
(a) the force exerted by the man,    N
$(b)$ the work done by the man on the piano,    J
$(c)$ the work done by the friction force,   J
$(d)$ the work done by the force of gravity,   J
$(e)$ the net work done on the piano   J


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  
  (a) Find the force requiredgjgpbkbl g n3c+tf2:/r;m15h to give a helicopter of mass M an acceleration of 0.10 g 3c+ j 1p/nrbktgflh:2bmg 5;g upward.    Mg
(b) Find the work done by this force as the helicopter moves a distance h upward.    Mgh

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  
  $\text{What is the minimum work needed to push a 950-kg car 810 m up along a 9.0$^{\circ} $ incline? }$$(a)\text{ Ignore friction. }$    J
$(b)\\\text{Assume the effective coefficient of friction retarding the car is }0.25.$    J

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  
  In Fig. 6-6a, assume the distance axis is li4hqc ;m 2xqat s8guu4+near and that $d_{\mathrm{A}}=10.0$ m and $d_{\mathrm{B}}=35.0$m. Estimate the work
done by force $F$ in moving a 2.80-kg object from $d_\mathrm{A}$ to $d_\mathrm{B}$   J



参考答案:     查看本题详细解析

标记此题
37#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The force on an object, acting al;n. eq25uom 7ivvbyuw52m +ul ong the x axis, varies as shown in Fig. 6–37. Determine the work done by this force to move the objeceq +i5uuvl;mu 2v5wyo.72nb mt (a) from x=0 m to x = 10 m    J
(b) from x = 0 m to x = 15 m    J



参考答案:     查看本题详细解析

标记此题
38#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A spring has $k=88$ N/m. Use a graph to determine the work needed to stretch it from $x=3.8$ cm to
$x=5.8$cm, where $x$ is the displacement from its unstretched length    J

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  
  The net force exerted on a p 23w29 lnh*tllbo)kr32t(jej 1bpqxfarticle acts in the $+x$ direction. Its magnitude increases linearly from zero at
$x=0$, to 24.0 N at $x=3.0$ m. It remains constant at 24.0 N from $x=3.0$ m and then decreases
linearly to zero at $x=13.0$m. Determine the work done to move the particle from $x=0$ to $x=13.0$ m
graphically by determining the area under the $F_x$ vs. $x$ graph    J

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  
  At room temperature, an oxygen m 1rroat81wyv4 wi7 4zep pi,*eolecule, with mass of $5.31\times10^{-26}$typically has a KE of about$6.12\times10^{-21}$ J .How fast is the molecule moving?    m/s

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  
  (a) If the KE of an arrowtnhd t-fq6j *8 is doubled, by what factor has its speed increased? $ \sqrt{a}$ a =    (b) If its speed is doubled, by what factor does its KE increase?   

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  
  How much work is required to stop an elg9qqro: /lwl wl;0 z0bectron $\left(m=9.11\times10^{-31}\mathrm{~kg}\right)$ which is moving with a speed of$1. 90\times 10^{6}\mathbf{m/ s}$ ? $\boxed{a\times10^{b} \mathrm{J}}$ a =    b =   

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  
  How much work must be done to stop a n sv6)-9 7djmudz6c04l1 hs nn(uyea p1250-kgcar traveling at 105km/h?$\boxed{a\times10^b\text{J}}$ a =    b =   

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  
  An 88-g arrow is fired from a bow whose string exerts an averajf*h ; ywnuhha* bi.:8ge force of 110 N on the arrow over a disi*:.;a *u8 h fjbhhwnytance of 78 cm. What is the speed of the arrow as it leaves the bow?    m/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  
  A baseball (m=140kg) traveling 32m/s moves a fielder’s glove backwaonk3 6)izatjhjf 6:oyx+wk- ( rd 25 cm when the ball is caught. What was(6+6j ka ijkf txwooz:n) 3y-h the average force exerted by the ball on the glove?    N

参考答案:     查看本题详细解析

标记此题
46#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
If the speed of a car is increased by 50%, by what factor will its minic *kjtf 2iwfeh-:y; 9 4obd2vdmum braking distance be increased, assuming all else is the same? Ignore the driverv2fe-d*jk 9 :2 htcf4yobd;iw ’s reaction time.
参考答案:    

标记此题
47#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  At an accident scene on a level road, investigators measure a car’s skid yw x9rnh7 h0:yth+n/lmark to be 88 m long. The accident occurred on a rainy day, and the coefficient of kinetic friction was estimated to be 0.42. Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes. (Why does the ca9y7nxn0 r:t/+hhw lyh r’s mass not matter?)    m/s

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  
  A softball having a mass of 0.25 kg is pitched at By the time it reaches thyike;.obf 7x+p) t,nze plate, it may have slowed by 10%. Neglecting gravity, estimate the average force of air resistance during a pitch, if the distance between the plate and the pit7k;opb. +ztye) xfni,cher is about 15 m.    N

参考答案:     查看本题详细解析

标记此题
49#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How high will a 1.85-kg rock (+9 kh+keo+qblrl0qqgo if thrown straight up by someone who does 80.0 J of work on it? Neglect ai +boleqqhk rl9+q(0k+r resistance.    m

参考答案:     查看本题详细解析

标记此题
50#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 285-kg load is lifted 22.0 m vertically withe*b89: gqkyl,-i n4l1v5l2kicp gecu an acceleration by a single cable. Determine,eb5gi1n48lk 9p2i:lcg cqvlk - eyu*
(a) the tension in the cable,    N
(b) the net work done on the load,    J
(c) the work done by the cable on the load,    J
(d) the work done by gravity on the load,    J
(e) the final speed of the load assuming it started from rest.    m/s

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  
  A spring has a spring j7i (c :ft szhr9kw:e29wzacq)d((vistiffness constant, k, of 440N/m How much must this spring be stretched to store 25 J of potentiaf9i(a (s)w 7k (9h2zw t:qce:z rijdvcl energy?    m

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  
  A 7.0-kg monkey swings from one branch to another 1.2 m higher./(mwf0qy59bfejyt9 pf r sl7 8:bw t5e What is the change in potmptr5web0f:eq yfjy8w( f5t sl 9/79bential energy?    J

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  
  By how much does the gravitational pot9vvvrhjo.x6 cfvelq0 70.) otential energy of a 64-kg pole vaulter change if his center of mass rrq )v .eo9c0t 6h07vlvv.xjo fises about 4.0 m during the jump?    J

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 1200-kg car rolling on a horizontal surface has speed k+x,7e0)l xzqdki k,rv = 65 km/h when it strikes a horizontal coiled spring and is brought to rest in a distance of 2.2 m. What is the spring stiffness constant of td kkxx+z0 li)q,ek7 r,he spring?    N/m

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  
  A 1.60-m tall person lifts a 2.10-kg book froz x-rhxf9 :kl(m the ground so it is 2.20 m above the ground. What is the potential energy of the book refx hk9z-:xr( llative to
(a) the ground,    J
(b) the top of the person’s head?    J
(c) How is the work done by the person related to the answers in parts (a) and (b)?    J

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  
  A 55-kg hiker starts at an elevation of 1600 m and climbs to the top of a 3300-m7. i) jxi; fpppwuz)1t peak. 1.)p)ifz;ppwiu x jt7
(a) What is the hiker’s change in potential energy?    J
(b) What is the minimum work required of the hiker?    J
(c) Can the actual work done be more than this? Explain why. 

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  
  A spring with k = 53N/m hangs verticalwdj z56v cmud+g s;*sk7mmpgau 8 -)9zly next to a ruler. The end of the spring is next to the 15-cm mark on the dc uz8ju6 m* gsdk)7+-p 9 ;gsmazmw5vruler. If a 2.5-kg mass is now attached to the end of the spring, where will the end of the spring line up with the ruler marks?    cm

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  
  Jane, looking for Tarzan, is rupc(dksl (w8 x-nning at top speed (5.3m/s) and grabs a vine hanging vertically from a -8d cx(k w(lsptall tree in the jungle. How high can she swing upward?    m
Does the length of the vine affect your answer? 

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 novice skier, startih.e 4(av3z-ekdo+ tni ng from rest, slides down a frictionless 35.0$^{\circ}$ incline whose vertical height is 185 m. How fast is she going when she reaches the bottom?    m/s

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 sled is initially given a shove up+e/g llajuzep /wf+l00c 7kq/)s)zf h a frictionless 28.0$^{\circ}$ incline. It reaches a maximum vertical height 1.35 m higher than where it started. What was its initial speed?    m/s

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  
  In the high jump, Fran’s kinetic energy is transformed into grmkjxbq+x,6 w- avitational potential energy without the aid of a pole. With what minimum speed must Fran leave the ground in ordemb6w ,x+jx-q kr to lift her center of mass 2.10 m and cross the bar with a speed of 0.7m/s.    m/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  
  A 65-kg trampoline artist jumv42jzgb.; xw,6ay s fpps vertically upward from the top of a platform with a speed of 26zg 4fpa,xb w.sj vy;5.0 m/s. ($\alpha)$ How fast is he going as he lands on the trampoline, 3.0 m below (Fig. 6-38)?$v_2$ $\approx$    m/s
(b) If the trampoline behaves like a spring with spring stiffness constant 6.2×10$^{4}$ N/m , how far does he depress it? $y_3$ =    m


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  
  $\text{A projectile is fired at an upward angle of 45.0o from the top of a 265-m cliff with a speed of 185m/s. What will}\\\text{be its speed when it strikes the ground below?(Use conservation of energy.)}$    m/s

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 vertical spring (ignore its mass), whose spring stiffness constant is 950N/mjcpr12 r)g yi l:uad.) is attached to a table and is compressed down 0.150 m. (a) What upward sp):gy rui a12cj l.)dpreed can it give to a 0.30-kg ball when released?    m/s
(b) How high above its original position (spring compressed) will the ball fly?    m

参考答案:     查看本题详细解析

标记此题
65#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A block of mass m slides without friction along the looped track shownz:tq64uduulz .xha.298 lt ep in Fig. 6–39. If the block is to remain on the track, even at the top o ud .le 2zq.uz:6t8lpa 9xhut4f the circle (whose radius is r), from what minimum height h must it be released?    r


参考答案:     查看本题详细解析

标记此题
66#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
A block of mass m is attached to the en l*cv:equ70lqh5 c e2xd of a spring (spring stiffness constant k), Fig. 6–40. The blec 50lhce2qvu l7:qx*ock is given an initial displacement $x_0$ after which it oscillates back and forth. Write a formula for the total mechanical energy (ignore friction and the mass of the spring) in terms of $x_0$ position x, and speed

参考答案:    

标记此题
67#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 62-kg bungee jumper jumps frt-zw0fs xc31 oijgj2k7i1v1 gom a bridge. She is tied to a bungee cord whose unstretched0wzk1tx v ii17 2fg1jj3-s ocg length is 12 m, and falls a total of 31 m. (a) Calculate the spring stiffness constant k of the bungee cord, assuming Hooke’s law applies. $\approx$    N/m
(b) Calculate the maximum acceleration she experiences. $\approx$   m/$s^2$

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  
  The roller-coaster carsz75i ui2z f,5)gz; a*w:0pkdxk xmvp shown in Fig. 6–41 is dragged up to point 1 where it is released from rest. Assuming no frisgawzmp xi;:vi k,u0 f d7 5pz2)k*zx5ction, calculate the speed at points
2    m/s
3    m/s
4    m/s


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 0.40-kg ball is thrown with a speed y6tosts-d8g;;c:o chthf5 /2b btn(uof 12 m/s at an angle of 33 $^{\circ} $. (a) What is its speed at its highest point    m/s
(b) how high does it go? (Use conservation of energy, and ignore air resistance.)   m

参考答案:     查看本题详细解析

标记此题
70#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
An engineer is designing a spring to be placed at the bottom of an elevator sh(s9/czsqxa y pk7o *j1aft. If the elevator cable should break when the elevator is at a height h above the top of the spring, calcu 7s kq posc9/(1jyzax*late the value that the spring stiffness constant k should have so that passengers undergo an acceleration of no more than 5.0 g when brought to rest. Let M be the total mass of the elevator and passengers.
参考答案:    

标记此题
71#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A cyclist intends to cycle up 6 w nxbl ta-,r3ymgj+,a 7.8 $^{\circ} $ hill whose vertical height is 150 m. Assuming the mass of bicycle plus cyclist is 75 kg,
(a) calculate how much work must be done against gravity.    J
(b) If each complete revolution of the pedals moves the bike 5.1 m along its path, calculate the average force that must be exerted on the pedals tangent to their circular path. Neglect work done by friction and other losses. The pedals turn in a circle of diameter 36 cm.    N

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  
  Two railroad cars, each of mass 7650 kg y;)ljttxl.d,povx1 m(gql5 6 and traveling 95km/h in opposite directionso (d;xlvlg.1t5y )x6 m,tjlqp, collide head-on and come to rest. How much thermal energy is produced in this collision? $a\times10^b$ J a =    b =   

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  
  A 21.7-kg child descends a slide 355 c) 7 q qdi,ud aw8f-vs+7xonzsxe*f.5 m high and reaches the bottom with a speed of 2.2m/s How much thermal energy due to friction was generated in this proces)sq+ , x7n oc*wzdixqudfvsa75f e-58s?    J

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 ski starts from rest and vq1c nr9s v)ehgwiy3ck-e(t;;,0qm lslides down a 22 $^{\circ} $ incline 75 m long.
(a) If the coefficient of friction is 0.090, what is the ski’s speed at the base of the incline? $\approx$    m/s
(b) If the snow is level at the foot of the incline and has the same coefficient of friction, how far will the ski travel along the level? Use energy methods.$\approx$    m

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  
  A 145-g baseball is dropped from a tree 13.0 m above the ground. +m yobm 5m,t(m
(a) With what speed would it hit the ground if air resistance could be ignored?    m/s
(b) If it actually hits the ground with a speed of 8m/s what is the average force of air resistance exerted on it?    N

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  
  You drop a ball from a heic g,cc5ob08ot y3)lf yght of 2.0 m, and it bounces back to a height of 1.5 mg8o yof l0c3b)5cy,t c.
(a) What fraction of its initial energy is lost during the bounce?    %
(b) What is the ball’s speed just as it leaves the ground after the bounce?    m/s
(c) Where did the energy go?

参考答案:     查看本题详细解析

标记此题
77#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 110-kg crate, starting from rest, is pulled across a floor with a cs(xz yds 5(rb95;x7 tvexmn-e onstant horizontal force of 350 N. For the first 15 m the floor is frictionless, and for the next 15 m the coefficient of friction is 0.30. What is the final speed of the crate? vs79bd ( (xeyxx;mte5nr-z5 s   m/s

参考答案:     查看本题详细解析

标记此题
78#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose the roller coaster in Fig. 6–41 passes point 1 we sugj ;)7e9)e-cg5 3rvamcyi ith a speed of If the a35 aiu)9g ve);m7 g-cejcsyre verage force of friction is equal to one-fifth of its weight, with what speed will it reach point 2? The distance traveled is 45.0 m. $\approx$    m/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 skier traveling 12m/s reaches theq :0lpb)qlv3v foot of a steady upward 18.0 $^{\circ} $ incline and glides 12.2 m up along this slope before coming to rest. What was the average coefficient of friction?   

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 0.620-kg wood block is firmly attached to a very light horizontal - rr x*lggs6w4q:t pn)r x-uq7spring (k=180N/m) as shown in Fig. 6–40. It is noted that the block–spring system, when compressed 5.0 cm and released, stretches out 2.3 cm beyond the equilibrium position before stopping and turning baq*twr x-r:g74sp grx-q 6nu)lck. What is the coefficient of kinetic friction between the block and the table?   


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 280-g wood block is firmly attached to a very light hortp*rly 50l*sl4 w2koaizontal spring, Fig. 6–40. The block can slide along a table where the coefficient of friction is 0.30. A force of 22 N compresses the spring 18 cm. If the spring is released from krt l5*l2s paw04*lyo this position, how far beyond its equilibrium position will it stretch on its first swing?    m

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  
  Early test flights for the space shuttle used a “glider” 4hhv h).vd;y s(mass of 980 kg including pilot) that was launched horizontally at 500km/h from a height of 3500 m. The g.hsv h4d;)yvhlider eventually landed at a speed of 200km/h (a) What would its landing speed have been in the absence of air resistance?$\approx$    km/h
(b) What was the average force of air resistance exerted on it if it came in at a constant glide of 10 $^{\circ} $ to the Earth?$\approx$    N

参考答案:     查看本题详细解析

标记此题
83#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How long will it take a 1750-W motor to liftzletcwh 9u t0 xh(;w(+ a 315-kg piano to a sixth-story window 16.0 h(hle; 9x0+c(uwzttw m above?    s

参考答案:     查看本题详细解析

标记此题
84#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If a car generates 18 hp when travel5 ksm3 n6lzk6jy8wl(d ing at a steady 88km/h what must be the average force exerted on6 8dzlskwyl36kj 5( nm the car due to friction and air resistance?    N

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 1400-kg sports car accelerates from rest to 95km/h in 7.4 s. Whdg) :ehgr tpp96 dyv66*woq 9zat is the average power):9 e oy9 *phv6td6gpqgr dz6w delivered by the engine?$\approx$    hp

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) Show that one Britis4 f cvb-265zmyx4 rwa;zap -wch horsepower$ \mathrm{ft}\cdot\mathrm{lb/s}$ is equal to 746 W.
(b) What is the horsepower rating of a 75-W light bulb?    hp

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  
  Electric energy units are oft a)sxzr)93phnit:ya): kd xo 7en expressed in the form of “kilowatt-hours.”
(a) Show that one kilowatt-hour (kWh) is equal to $3.6\times10^6$J
(b) If a typical family of four uses electric energy at an average rate of 520 W, how many kWh would their electric bill be for one month $\approx$   kW*h
(c) how many joules would this be?$a\times10^b$ J a =    b =   
(d) At a cost of 0.12 dollars per kWh, what would their monthly bill be in dollars? Does the monthly bill depend on the rate at which they use the electric energy?    dollars

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  
  A driver notices that her 1150-kg car slows down from to 65km/h in aboumr: u u 4. wac,6v*rp+vagb8,eqlh9iat 6.0 s on the level when it is in neutral. Appro rpu*g:.al a+ba, ruc m vweq,6ihv498ximately what power (watts and hp) is needed to keep the car traveling at a constant 75km/h.    hp

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  
  How much work can a 3.0-hp motor do in 1.0 hmh8hk2wvd a3 pd ;grdj,,xb)+ ? $a\times10^b$ J a =    b =   

参考答案:     查看本题详细解析

标记此题
90#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A shot-putter accelerates a 7.3-kg shot from rest to 14mcg;v+n,3e.df-ldwn 0 )lzraz/s If this motion takes 1.5 s, what averag,-n c0l .zfa;wn lded+)v3rz ge power was developed?$\approx$    W

参考答案:     查看本题详细解析

标记此题
91#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A pump is to lift 18.0 kg of water per minuo94 vnif)g 2r ieerci44;c1jqte through a height of 3.60 m. What output rating (watts) si12;r qogf4c r94j c)v4 ieneihould the pump motor have?    W

参考答案:     查看本题详细解析

标记此题
92#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  During a workout, the football playerspn;fz 2 sm:,3mu5wnq,ul cfr+ at State U. ran up the stadium stairs in 66 s. The stairs are 140 m long and inclined at an angle of u:lm+cw q;n3,zps nf52m ,fru32 $^{\circ} $. If a typical player has a mass of 95 kg, estimate the average power output on the way up. Ignore friction and air resistance.    W

参考答案:     查看本题详细解析

标记此题
93#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How fast must a cyclist climb aq;v(o)()gj zmzqn/h v 6.0 $^{\circ} $ hill to maintain a power output of 0.25 hp? Neglect work done by friction, and assume the mass of cyclist plus bicycle is 68 kg.   m/s

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 1200-kg car has a maximum power output of 120 hp. How st3 3 decg9v o/6ev/uuhdeep a hill can it climb at a constant speed of 75km/h if the frictional forces add3 uhd 9gc//ovee3vu d6 up to 650 N?    $^{\circ} $

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  
  What minimum horsepower must a motor h5xlfg) juje0 6.gds t*ave to be able to drag a 310-kg box along a level floor at a speed e uf*t05lg. jg)xjd6sof 1.2m/s if the coefficient of friction is 0.45?    hp

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 bicyclist coasts down a 7.byfjm6+j 7)* uk7s hyq0 $^{\circ} $ hill at a steady speed of 5m/s Assuming a total mass of 75 kg (bicycle plus rider), what must be the cyclist’s power output to climb the same hill at the same speed?    W

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  
  Designers of today’s cars have built “5mi/h(8km/h) bumpers” that are designed 8qcje2gof5rh nq3gq-br6 6a(to compress and rebound elastically without any physical damage at speeds below 8km/h If the material of the bumpers permanently deforms after a compression of 1.5 cm, but remains like an elastic spring up to that point, what must the effective spring stiffness constant of the bumper be, assuming the car has a mass of 1300 kg and is tested by ra2a85 jg q(or6 rcbgqq-e36fhnmming into a solid wall? $a\times10^b$ N/m a =    b =   

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  
  In a certain library the firstys+*s8a idzm / shelf is 10.0 cm off the ground, and the remaining four shelves are each spaced 30.0 cm above the previous one. If the average book has a mass of 1.5 kg with a height of 21 cm, and an average shelf holds 25 books, how much work is required to y/s dm+*si8azfill all the shelves, assuming the books are all laying flat on the floor to start? $\approx$    J

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  
  A film of Jesse Owens’s famous longuh*ne4uley su(41yt :j/ , ito jump (Fig. 6–42) in the 1936 Olympics shows that his center of mass rose 1.1 m from launch point to the top of the arc. What minimum speed did he need at launch if he was traveling at 6.5m/(uusnh:,t*e jy41ult iyo 4/es at the top of the arc?   m/s

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  
  The block of mass m aq vqub 43 qu rmm+za60my8v86sliding without friction along the looped track shown in Fig. 6–39 is to remain on the track at all u6vq64ma+q0z 8a8yb 3ummqrvtimes, even at the very top of the loop of radius r.
(a) In terms of the given quantities, determine the minimum release height h (as in Problem 40). Next, if the actual release height is 2h, calculate    r
(b) the normal force exerted by the track at the bottom of the loop,    mg
(c) the normal force exerted by the track at the top of the loop,   mg
(d) the normal force exerted by the track after the block exits the loop onto the flat section.   mg


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  
  An airplane pilot fell 370 m after jumping from an aircraft wj*u42q17qbgx 91fk and r9hptithout his parachute opening. He landed in a snowbank, creating a crater 1.1 m deep, but survived with only minor injuries. Assuming the pilot’s mass was 78 kg and his terminal vel 9aqb qgj1t7pdr 2f*49uxhnk1ocity was 35m/s estimate
(a) the work done by the snow in bringing him to rest; $\approx$    J
(b) the average force exerted on him by the snow to stop him;$\approx$    N
(c) the work done on him by air resistance as he fell.$\approx$    J

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 ball is attached to a horizontal cord of length L whose other end is fif,(9ml- i.rh yvzp8xa xed (Fig. 6–y,9x(8-z pfv rh.laim 43).
(a) If the ball is released, what will be its speed at the lowest point of its path?
(b) A peg is located a distance h directly below the point of attachment of the cord. If h=0.8L what will be the speed of the ball when it reaches the top of its circular path about the peg?
参考答案:    

标记此题
103#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 65-kg hiker climbs to the tom1j8b n .rxfa+p of a 3700-m-high mountain. The climb is made in 5.0 h starting at an elevation of.+xj8nramb1 f 2300 m. Calculate
(a) the work done by the hiker against gravity,   
(b) the average power output in watts and in horsepower,   W    hp
(c) assuming the body is 15% efficient, what rate of energy input was required.    hp

参考答案:     查看本题详细解析

标记此题
104#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An elevator cable breaks when a 920-kg elevatotx2* 6yidnu/zyq8rs/b mjd ; wix3/ 0ir is 28 m above a huge spring ($k=2.2\times10^{5} \mathrm{N/m}$) at the bottom of the shaft. Calculate
(a) the work done by gravity on the elevator before it hits the spring,$\approx$    j
(b) the speed of the elevator just before striking the spring,$\approx$    m/s
(c) the amount the spring compresses (note that work is done by both the spring and gravity in this part).    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  
  Squaw Valley ski area in Calxx4xm198klt3i x 7gf tifornia claims that its lifts can move 47,000 people per hour. If the average lift carries people about 200 m (vertically) higher, eg x9i3l7fm4k 1t8x xtxstimate the power needed.$a\times10^b$ W a =    b =   

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  
  Water flows over a dam at the rate of 650kg/s and 1.o7ye z)qgsbuv9t d0al qf+ 8falls vertically 81 m before striking the turbine bladlg+a70) q dbqvesfut1zy8 o9 .es. Calculate
(a) the speed of the water just before striking the turbine blades (neglect air resistance), $\approx$    m/s
(b) the rate at which mechanical energy is transferred to the turbine blades, assuming 58% efficiency.    W

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  
  Show that on a roller coaster with a circular verti ; z0cpfk2cgi-cal loop (Fig. 6–44), the difference in your apparent weight at the top of the circular loop and the bottom of the circular loop is 6 g’s — that is, six times your weight. Ignore friction. Show also that as long as your speed is above the minimum needed, this answer doesn’t depend on the size g0pc2f-cizk; of the loop or how fast you go through it.    mg


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) If the human body could convert a candy bar direc jwjskt.(8.y2eot4msw ,riq-: 3q jfntly into work, how high could an 82-kg man cli-myf2rts(qj ew84o w. j :.3n,sjtkqimb a ladder if he were fueled by one bar (=1000kJ)    m
(b) If the man then jumped off the ladder, what will be his speed when he reaches the bottom?    m/s

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  
  A projectile is fired at an upward angle o*w5u0el gnup*36zjg hf 45.0$^{\circ} $ from the top of a 165-m cliff with a speed of 175m/s What will be its speed when it strikes the ground below? (Use conservation of energy and neglect air resistance.)    m/s

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  
  If you stand on a bathej;fd 5uhk- 5a97yqjs3 0qkqwroom scale, the spring inside the scale compresses 0.60 mm, and it tells you your weight is 710 N. Now if you du3 jqk-e 90aqq;fjwk7s y5h 5jump on the scale from a height of 1.0 m, what does the scale read at its peak?    N

参考答案:     查看本题详细解析

标记此题
111#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 65-kg student runs at 5m/s grabs a rope, and swings out sov 2-bfo7ot-over a lake (Fig. 6–45f 7 ost2vo-b-o). He releases the rope when his velocity is zero.
(a) What is the angle when he releases the rope?    $^{\circ} $
(b) What is the tension in the rope just before he releases it?    N
(c) What is the maximum tension in the rope?    N


参考答案:     查看本题详细解析

标记此题
112#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In the rope climb, a 7h7 y bbj 9;6ve tbv:e,juhy-:v2-kg athlete climbs a vertical distance of 5.0 m in 9.0 s. What minimum power output wasj; 9buyvv 6 -b h,:tjv7:eheby used to accomplish this feat?    W

参考答案:     查看本题详细解析

标记此题
113#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Some electric-power companie55qvk,h6r 7a-ofj dd(g * zkhds use water to store energy. Water is pumped by reversible th,k*da rkqfj755v-(dh d o6z gurbine pumps from a low to a high reservoir. To store the energy produced in 1.0 hour by a 120-MW ($120\times10^{6}$W) electric-power plant, how many cubic meters of water will have to be pumped from the lower to the upper reservoir? Assume the upper reservoir is 520 m above the lower and we can neglect the small change in depths within each. Water has a mass of 1000 kg for every 1$m^3$.    $m^3$

参考答案:     查看本题详细解析

标记此题
114#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A spring with spring stiffness constant k is cut in ha )(,;(yj fa yajj--ydgr p0m:imxfvu (lf. What is the spring stiffness constant for each of the twomyajig :m-;u) p ((yy(d0jvja-xf,f r resulting springs?   k

参考答案:     查看本题详细解析

标记此题
115#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 6.0-kg block is puspgcs ; 9lg3zc4hed 8.0 m up a rough 37 $^{\circ} $ inclined plane by a horizontal force of 75 N. If the initial speed of the block is 2.2m/s up the plane and a constant kinetic friction force of 25 N opposes the motion, calculate
(a) the initial kinetic energy of the block; $\approx$    J
(b) the work done by the 75-N force; $\approx$    J
(c) the work done by the friction force;    J
(d) the work done by gravity;$\approx$    J
(e) the work done by the normal force;    J
(f) the final kinetic energy of the block.$\approx$    J

参考答案:     查看本题详细解析

标记此题
116#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If a 1500-kg car can accelerate from 35kmnkq* -+05bir rfgknpmz9j o g233j t1x/h to 55km/h in 3.2 s, how long will it take to accelerate from 55km/h to 75km/h Assume the power stays the same, and 1mz+nf 3* ktj0n 39-gxg jq2bkipro5rneglect frictional losses.    s

参考答案:     查看本题详细解析

标记此题
117#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a common test for cardiac function (the “stress test”), the patient walks sow9p.0m9n+ n i.uoig9udqc/ on an inclined treadmill (Fig. 6–46). Estimate the power required from a 75-kg patient when the treadmill is sloping at i. 9nu99iu o mocn .qp+w0dgs/an angle of 15 $^{\circ} $ and the velocity is 3.3km/h (How does this power compare to the power rating of a light bulb?)$\approx$    W

参考答案:     查看本题详细解析

标记此题
118#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  (a) If a volcano spews a 500-kg rock ulz awe -11 iwkddq9*/vertically upward a distance of 500 m, what * iz1kad qu91w ew-/ldwas its velocity when it left the volcano? $\approx$    m/s
(b) If the volcano spews the equivalent of 1000 rocks of this size every minute, what is its power output? $\approx$ $a\times10^b$ W a =    b =   

参考答案:     查看本题详细解析

标记此题
119#
 
填空题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Water falls onto a wat jwm,tpk-*wqk u8+ ey h55sb.ner wheel from a height of 2.0 m at a rate of 95kg/s (a) If this wate hwp-j m5.+ybskqe8 n*k5uw,tr wheel is set up to provide electricity output, what is its maximum power output?    W
(b) What is the speed of the water as it hits the wheel?    m/s

参考答案:     查看本题详细解析

  • :
  • 总分:119分 及格:71.4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 119 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|使用帮助|手机版|切到手机版|题库网 (https://tiku.one)

    GMT+8, 2024-12-26 03:12 , Processed in 0.358987 second(s), 259 queries , Redis On.