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习题练习:Physics Unit6: Work and Energy



 作者: admin发布日期: 2022-07-28 12:33   总分: 95分  得分: _____________

答题人: 匿名未登录  开始时间: 22年07月26日 13:45  切换到: 整卷模式

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1#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the correct unit of work expresrc)air7q*avtt z( l-3 sed in SI units?

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2#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Can work be done on a sarz g563n xmphuk qz(e4* +,frystem if there is no motion?

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3#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If you push twice as hard against a stationaryt lmi 7dfga*;-j 0uq)p brick wall, the amount of work you dd0laj7ug* q t)i;fmp-o

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4#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 50-N object was lifted 2.0 m vertically and is being held there. How mu*2ek4*hl jkcd5kqy95 vn v7bjch work is being done i2jv5b*qkv 4j7k*dh5ck en9 lyn holding the box in this position?

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5#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If you walk 5.0 m horizontally forward at a c33.x7g5trl ly/8 jjn w3xyjtgonstant velocity carrying a 10-N object, the xl g./tx wjny g5t8y7l3j3jr3amount of work you do is

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6#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A container of water is lifted vertically 3.0 m then returned to its -y. wirtx) x9eoriginal position. If the total weight is 30 N, how much work xx-)ty.we ri9was done?

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7#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Does the centripetal force acting on an object do work on the objecxxmwxetupk*zy)j)2++ h .eo 2t?

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8#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You throw a ball straight r smq))7cr*q3: lxb hnup. Compare the sign of the work done by gravity while the ball goes up with the signc :r 3h7 xrqbqns))ml* of the work done by gravity while it goes down.

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9#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The area under the curve, on a Force versus position (F vs. x) graph, represent7qcatl 2.b.aw sw aac7lb..q2 t

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10#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  On a plot of Force versus position (F vs. x), wh)3vp3gl7u 3nal b 4pwrat represents the work done by thb) 3rplnu3g34vl 7paw e force F?

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11#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The quantity $\frac{1}{2} \; mv^2$ is

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12#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the net work done on an object is positive, then the objeca bbek6k+9 aq+r2w d7lt's kinetic energy

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13#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the net work done on an object is netb((g amwz. 1 aw j 1zt8szs:m(6ick2xahrl,1gative, then the object's kinetic energy

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14#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the net work done on an object is zero, then the obdwp5uqz8yc x4g-gw8 .ject's kinetic energy

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15#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A truck weighs twice as much as a car, and is moving at twice the speed of th9eoll . b3gnhcx)b. 2ge car. Which statement is true about the truck's kinetic energy compared to that of the eblc92 .gg)3.nxh lbo car?

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16#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Car J moves twice as fast as car K, and car J has half the mass of car Khll dx*;)ouq (nsuz3omi7q8 1 . The kinetic energy of car J, compared to car K )ih ndlxz(sq ol;u*7m8u3o1q is

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17#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An object hits a wall and bounces back with half of its original speed. /uhpsyj 1 xir+dviz1ni2c1 .( What is the ratio of the final kinetic eneizir+ch1.jy is2 1dpunxv (1/rgy to the initial kinetic energy?

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18#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A brick is moving at a speed of 3 m/s and a p9c2xs nj+ek-pebble is moving at a speed of 5 m/s. If both obj cjx+e9kp 2-nsects have the same kinetic energy, what is the ratio of the brick's mass to the rock's mass?

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19#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 4.0-kg mass is moving with speed 2.0 m/s. A 1.0-kg mass a,1si :hj lma6is moving with speed 4.0 m/s. Both objects encounter the same constant braking fl1jaha, ism 6:orce, and are brought to rest. Which object travels the greater distance before stopping?

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20#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You slam on the brakes of your k a: ,w5xe93;dkk 4nmvifvk )ecar in a panic, and skid a certain distance on a straight, level road. If you had been tvkak ,:n)5ev f k;d4i9xk 3ewmraveling twice as fast, what distance would the car have skidded, under the same conditions?

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21#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A planet of constant mass o4qb w.2np unhg7gs/wa*i28 bl rbits the Sun in an elliptical orbit. Neglecting any friction effects, what happens to the lwai g.7h * 8 4/bnwbq22sgupnplanet's kinetic energy?

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22#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
State the work-energtul 100 14hxhjz w;fygy principle.
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23#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The quantity mgy is

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24#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The quantity $\frac{1}{2} \; kx^2$ is

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25#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Is it possible for a system to have negative potential energy?-; ne;vltjae :yaz;p.w38g yr

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26#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An object is released from resty0l ad,a.zjj01;paj s a height h above the ground. A second object with four times the mass of the first if released from the same height. The potential energy of the second object compared to t zal0ad0yj;j. ,ja p1she first is

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27#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 0.200-kg mass attached to the end of a spring causesu8cctz84ko efd 4dv :6 it to stretch 5.0 cm. If another 0.200-kg mass is added to the spring, the potential energy of the spring will beev8 d:4c utzd84fok6c

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28#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The total mechanical ene*4fqpqz 6ynp -rgy of a system

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29#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An acorn falls from a t9uxrm)j ahmwr6.nz *+ri;c8o ,snit7 ree. Compare its kinetic energy K, to its potential energy z.rtuh in*xw o sr;ca+mm69r ,j)87i nU.

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30#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Describe the energy of a car drivin5t l xiww 2dtz:.4; aw+4corlrg up a hill.

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31#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A lightweight object and /umpc5miii m y9-(3yy a very heavy object are sliding with equal speeds along a level frictionless surface. They both slide up the same frictionlm39/5m-mucy yii yip( ess hill. Which rises to a greater height?

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32#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two masses *yculex/v( ,q$m_{1}$ and $m_{2}$ at the top of two frictionless inclined planes. Both masses start from rest at the same height. However, the plane on which $m_{1}$ sits is at an angle of $30^{\circ}$ with the horizontal, while the plane on which $m_{2}$ sits is at $60^{\circ}$. If the masses are released, which is going faster at the bottom of its plane?

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33#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
State the principle of conservation of mechanical energy for conserc bktm : lax+uf3h/,)s2)oldivative forcesmt fx3sd b2lo)ku/, ilch): +a.
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34#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A ball falls from the top of a building, through the air (air frqfanx/b*w) xtdp-3c;iction is present), to the ground below. How3 pq*td /a-b xn)c;fxw does the kinetic energy (K) just before striking the ground compare to the potential energy (U) at the top of the building?

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35#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A ball drops some distance and gains 30 J of kinetic ene 7 bxlf)fjp1 q-6j;mtl/6roij rgy. Do not ignore air resistance. How much gra fb-) lrq pt6jmo f/71x;j6ljivitational potential energy did the ball lose?

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36#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A ball drops some distance and loses 30 J of gravitation 9;xrq r:hvmt+al potential energy. Do not ignore air resistance. How much kinetic energy d + mthvq:r9xr;id the ball gain?

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37#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
State the law of conserva /9t,xiy3b130z x34p/sg oq iouewlowtion of energy.
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38#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The quantity Fd/t isxa)it +q 2zyb,1fb/n t.jcl(m

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39#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the correct unit of power expre9- 6i9r uwtusissed in SI units?

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40#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Of the following, which is no cn9-b.69r2ck pinwv8 l.noo at a unit of power?

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41#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Compared to yesterday, you did 3 times the work in one-thir1sz3p i2f8jlufm* xbtl6 v .n3d the time. To do so, *.l 2 nfjfvi8zm3x1t3 usb6plyour power output must have been

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42#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  To accelerate your car at a constant accelerab g6itm++21ot3shbk c /,cavhaj 8-qn tion, the car's engine must

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43#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An object is lifted vertically 2.0 m a;d9t;rcumod)-z4om83l:umd son5z t nd held there. If the object weighs 90 N, hm-3; 8troscn:dl;d oz4odm 9tm)u5zu ow much work was done in lifting it?

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44#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You lift a 10-N physics book up in th:ohz 9vdn ;4 nm+ol8pbe air a distance of 1.0 m, at a constant velocity of 0.50 m/s. Whatdo9 np +v;mb4zl :o8hn is the work done by the weight of the book?

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45#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 500-kg elevator is pulled upward with a constant force of 550iryyqa7c80f n )p 4l2gu2 3.rhzs4fpa0 N for a distance of 50.0 m. Wlpgf4a2 ny 3 rry02f 7ausi.8c4zpqh)hat is the work done by the 5500 N force?

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46#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 500-kg elevator is pulled upward with a constant for x(ufd9qqg8b +ce of 5500 N for a distance of 50.0 m. What is the work done u(9g +bxdf qq8by the weight of the elevator?

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47#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 500-kg elevator is pulled upw + ciad7x;cvm1a 0ng6fard with a constant force of 5500 N for a distance of 50.0 m. What is the 0 6 aaiv7cgfxdm;nc+ 1net work done on the elevator?

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48#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 30-N box is pulled 6.0 mr0,ba*ff 46oct dkw lw8a9: ee up along a $37^{\circ}$ inclined plane. What is the work done by the weight (gravitational force) of the box?

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49#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 4.00-kg box of fruit slides 8.0g u/05 h7thvz10v yyrk m down a ramp, inclined at $30^{\circ}$ from the horizontal. If the box slides at a constant velocity of 5.00 m/s, what is the work done by the weight of the box?

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50#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Matthew pulls his little sister Sarah in a sled on an icy surface (assume/yk(i0*wipf b9x7ejjp v 5a3n no friction), with a force of 60.0 N at an axk3 /n*5 fjpjyi7(0 e9awvpbingle of $37^{\circ}$ upward from the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew?

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51#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A force moves an object in the directi1ao i9ht fm,kn5f (r-won of the force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves from 0 to,f1i n5tam hw-(9krof 2.0 m.


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52#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A force moves an object in the direction of the force. The graph in F+wxc 7i rwg n+waaudy8,1v+ .qig. 6-1 shows the force versuc y .,+8wd1n a 7wrv+a+giqxwus the object's position. Find the work done when the object moves from 2.0 to 4.0 m.


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53#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A force moves an object in the direction of the force. The graph in Fig. 6-1 se x ym)j*ut48jhows the force versus the object's position. Find the work done when the object moves from 4.0 to 6ytuxm 4)e j*8j.0 m.


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54#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A force moves an object in the x o* *ubr4 uv7ii6jl, ja9n nwol-;6dqdirection of the force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves,j* -ovdi*lqjxna6i;974bnr u uwlo 6 from 0 to 6.0 m.


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55#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A horizontal force of 200 N is applied to movq0*ko ftn:zpca1nwfc/yxgc58 ) / s0 ae a 55-kg cart (initially at rest) across a 10 m level surface. Wfk) any f cpnxc05z:/q*s0/ a8og c1twhat is the final kinetic energy of the cart?

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56#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A horizontal force of 200 N is applied to move a 5spiv9.o 8mq42ob1a.0 kucko w5-kg cart (initially at rest) across a 10 m level surface. What is the final 9.c8iqv0so2k4u.o1 w aokmp bspeed of the cart?

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57#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 10-kg mass is moving with a speedb m6f f0p3l4bv of 5.0 m/s. How much work is required to stop the mass?m0bl3vb 6pff 4

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58#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If it takes 50 m to stop 5vstr m(t,iyb 0 3lzp6a car initially moving at 25 m/s, what distance is required to stop a car moving at 50 m/s lrv6ts35tz b0i(m, yp under the same condition?

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59#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A spring-driven dart gun propels a 10-g dart. It is9 zj -o,d7q k22rxgtfz9iy/vh 4wi*eq cocked by exerting a force of 20 N over a distance of 5.0 cm. With what speed will the dart leave the gun, assuming the spring has negligible ma f,ox2*kg-dt qw9qii4 vrh2/j zzey97ss?

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60#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 100-N force has a horizontal component of 80 N and a ;1i leou(zsgw;r c s9/vertical component of 60 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, 9cowre (;s;1/g lizusand moves 2.0 m horizontally along the floor. What is the cart's final kinetic energy?

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61#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An arrow of mass 20 g is shot horizontally into a bale of hay, snxm ws12h .l/lzxuq1t+j 7s(striking the hay withs/7utjw 1 s1l 2mh( sq+nx.xlz a velocity of 60 m/s. It penetrates a depth of 20 cm before stopping. What is the average stopping force acting on the arrow?

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62#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 15.0-kg object is moved from a height of 7.00 7stml0 dwpj/. .8jicmm above a floor to a height of 13.0 m above the floor. What is the change in gravitational.0stw8 jmm7 d i/pl.jc potential energy?

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63#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 400-N box is pushed up an inclined plane. The plane is 4.4c h u2a8kab,d0 m long and rises 2.0 m. If the plane is frictionless, how,4 kdba2a8 huc much work was done by the push?

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64#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 10-kg mass, hung onto a spring, causes the(;rqzcjicx-lby (zf9 ux c,pf;m;3i1 spring to stretch 2.0 cm. What is the spring const(cp zr;m3bfqxy9 -; ij1uc,lf; cz(xi ant?

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65#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A spring is characterized by a spring constant of q/qbc90pvl)ccc . 6nwlt :xhf(z65fp 60 N/m. How much potential energy does it store, when stretched bytv9nl/5lch(p:)f66q0c. qx zwfcp b c 1.0 cm?

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66#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Calculate the work reqqa x37cixk ;zc9iz, guh7 )w)a afc-n8uired to compress an initially uncompressed spring with a spring constant of 25 N/m by 10 cc ,cx ih7;gfzw3-) xkuna)czqa 8a7i9 m.

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67#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What work is required to stretch a spring of sprafo 0 3tob6sc(ing constant 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretched position itbfsc0o (a63 os at x = 0.)

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68#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A spring with a spring constant of 15 N/m is initially compressed by 3.0b+::f2s zai z1ope-tk cm. How much work is requirez:oa tb:ez +si-kpf21 d to compress the spring an additional 4.0 cm?

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69#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 60-kg skier starts from rest from the top of a 50-m high slope. b,+xhru. : apuWhat is the speed of the sli:pub,+ hax u.rer on reaching the bottom of the slope? (Neglect friction.)

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70#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A skier, of mass 40 kg, pushes off the top of rt( 5.o*arvq (l.- cofa0.qix q8wiqma hill with an initial speed of 4.0 m/s. Neglecting friction, how fast will sh (qofvm.rr 58 .-wq 0oqx*iiaqt(l.a ce be moving after dropping 10 m in elevation?

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71#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An object slides down a frictionl y++4ov yndpws3 y,,rbess inclined plane. At the bottom, it has a speed of 9.80 m/s. What is the vertical henp43wd ,br +oys v,+yyight of the plane?

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72#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1.0-kg ball falls to the floor. When it is 0.70 m above the f8 zw+pzbnn7xg *ik3z f4r2 l/dloor, its potential energy exactly equals if n734ikdp*zn+r zz xw8 l2/gbts kinetic energy. How fast is it moving?

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73#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A toy rocket, weighing 10 N, blasts straight up from groel.0*8p nl +nkfa(yyc9* ezydund level with a kinetic energy of 40 J. At the exact top of its trajectoryaey *ledn +kny.9*py0f (8lzc , its total mechanical energy is 140 J. To what vertical height does it rise?

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74#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A projectile of mass m leaves the grhq 5py:*a ;boe-; 4k,hv fhjfmound with a kinetic energy of 220 J. At the highest point in its trajectory, its kinetic energy is 120 J. To what vertical height, relative to its launch point, did it ;a*e , 4omfvkpfbh-qh;j h5y: rise?

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75#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A roller coaster starts from rest at a po n mov10wpqdn)-p+j0n int 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bot)-pw nnpmn 0ovd1j+q0tom of the dip?


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76#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A roller coaster startsx2e;ej+ k;ijm with a speed of 5.0 m/s at a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster+j; xek m2;jei at the top of the next slope, which is 30 m above the bottom of the dip?


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77#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A roller coaster starts at a point 30 m above the bot1qs 5;.j tv6m/i n8qf oihw0tltom of a dip with a speed of 25 m/s (See Fig. 6-t /i1n8o lt5qijsq;wv0hm.6f 2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 45 m above the bottom of the dip?


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78#
 
  What is the minimum speed of the ball at the bottomh zu-36v ymnl/enl .n* of its swing (point

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79#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A:2.2 m/s

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80#
 
  难度:2

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81#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A pendulum of length 50 cm is pulled 30 cm away from the vertical axis and ;rbv6vb5dwn-uab:e0 cn4k 2v released from rest. What will be its speed at thek5n2 nbe0w:v;vb r4u-b 6acdv bottom of its swing?

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82#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1500-kg car moving at 25 m/s hits an initially un e:yp* wrifz498evu* ecompressed horizontal spring witw4y*9pv ee i*u rf:ze8h spring constant of $2.0 \times 10^6 \; N/m$. What is the maximum compression of the spring? (Neglect the mass of the spring.)

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83#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A driver, traveling at 22 m/s, slows down her 2000 kg car to stop for a rei(kt+t)n :yr cd light. What work is done by the friction force againstykcn)rt+t i( : the wheels?

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84#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The kinetic friction force between a 60.0-kg object and a horizona62o k t4z1nab)2n(hbhxbe9ntal surface is 50.0 N. If the iz n4bhb eo)9ka 6a2x(n2 ntb1hnitial speed of the object is 25.0 m/s, what distance will it slide before coming to a stop?

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85#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 12-kg object is moving on9ofejh )j.kqwg.15i4a ,xx ol a rough, level surface. It has 24 J of kinetic energy. The friction force on it is a constant 0.50 N. How far 1lk 5fag4 o , xj.hxqwj)i9eo.will it slide?

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86#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A force of 10 N is applied horizontally to a 2.0-kg massbjq 323u88c; 9v cjimc;xe twr on a level surface. The coefficient of kinetic friction between the mass and the surface 3ucti 8emr 2j;;wcx qcb9j38vis 0.20. If the mass is moved a distance of 10 m, what is the change in its kinetic energy?

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87#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 60-kg skier starts from rest from the top of a 50-m high slope. If the wor3+ b v8g6zyndak donezyg a6 b83dnv+ by friction is $-6.0 \times 10^{3} \; J$, what is the speed of the skier on reaching the bottom of the slope?

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88#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An 800-N box is pushed s1i6ilbmv7l e9p4j( eup an inclined plane. The plane is 4.0 m long and rises 2.0 m. It requires 3200 J of workvibe6 1islpl4 9 j(em7 to get the box to the top of the plane. What was the magnitude of the average friction force on the box?

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89#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 2.0-kg mass is released from rest at the top of a plane inclined at 20e above p45ogpce -;eu horizontal. The coefficient of kinetic friction betwee 4goc-pu; p5een the mass and the plane is 0.20. What will be the speed of the mass after sliding 4.0 m along the plane?

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90#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 30.0-N stone is droppe1qpd t-- ukmkmnm8, l3d from a height of 10.0 m, and strikes the ground with a velocity of 7.00 m/s. What average force of air friction acts onqu38lm-m m1n,pd tk-k it as it falls?

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91#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  At what rate is a 60i/wj: e.s c)ptvn,myd12id c; .0-kg boy using energy when he runs up a flight of stairs 10.0-m high, wj:i sc2/ddpne)im;ct ,1.yv in
8.00 s?

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92#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 10-N force is needed to move an ob3h i ()gpib9amf7kl/ +n+fqfmject with a constant velocity of 5.0 m/s. What power must be delivered to the object by th)lp fnab7 i(k m+q9f3if+g /mhe force?

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93#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How many joules of energy are used by a 1.0 hp mybki xx:r/bh9,*) bzjotor that runs for 1.0 hr? (1 hp = 79xy xh bir)kzjb*, :b/46 W)

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94#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A cyclist does work at the rate of 500 W while riding. H1bvj f))xkjt 0ow much force does her foot push with when she is tr1xjkf)vj) 0 btaveling at 8.0 m/s?

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95#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1500-kg car accelerateso (vwcuiwq.py r2d4kro4 jfay3c6w; 88+ o8oh from 0 to 25 m/s in 7.0 s. What is the average power delivocrw;kc8p882iwo qu4vy ( oy odjar6.3hf4+w ered by the engine? (1 hp = 746 W)

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