Physics Unit6: Work and Energy - 题库网 (tiku.one)

1#

What is the correct unit of wor m 1rr*eqj3ze2k expressed in SI units?

A. $kg m/s^2$

B. $kg m^{2}/s$

C. $kg m^{2}/s^2$

D. $kg^2 m/s^2$

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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 system if therev20 iah suq5k+ ysg03q is no motion?

A. Yes, if an outside force is provided.

B. Yes, since motion is only relative.

C. No, since a system which is not moving has no energy.

D. No, because of the way work is defined.

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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 stationary brick wall, the amount ofa6)1uain h pmbon :eh7znb7-6 work you6eib) zhh1a:7bnn np-m6 a7o u do

A. doubles.

B. is cut in half.

C. remains constant but non-zero.

D. remains constant at zero.

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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 tm9vmr6aepu2i 2 sd-n z34 w6ldhere. How much wordz 6mpw69324 r anlse-dvi2umk is being done in holding the box in this position?

A. more than 100 J

B. 100 J

C. less than 100 J, but more than 0 J

D. 0 J

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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 dq+g w 3b-1)jqbd0clrkw2i o+forward at a constant velocity carrying a 10-N objec 3cqr0-+b2)1wwqjd bok lig+dt, the amount of work you do is

A. more than 50 J.

B. equal to 50 J.

C. less than 50 J, but more than 0 J.

D. zero.

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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 bi7sj *pf4n)*8c suuuthen returned to its original position. If the total weight is 30 N, how much*iub8nc)uss7* ujp f4 work was done?

A. $45 \; J$

B. $90 \; J$

C. $180 \; J$

D. No work was 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 onmjx xhh;rnf+l w: :ir.i;7xs6 an object do work on the object?

A. Yes, since a force acts and the object moves, and work is force times distance.

B. Yes, since it takes energy to turn an object.

C. No, because the object has constant speed.

D. No, because the force and the displacement of the object are perpendicular.

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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 up. Compare thet l0b p8.,whe9xafz *nb9lg) q sign of the work done by gravity while the ball goes up with the sign of the wor9* g0anew) t9xblzh,ql.fb 8pk done by gravity while it goes down.

A. Work is + on the way up and + on the way down.

B. Work is + on the way up and - on the way down.

C. Work is - on the way up and + on the way down.

D. Work is - on the way up and - on the way 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 p2)qz ae4 g jcwcevnbwen pvg 2z0-/758osition (F vs. x) graph, representscvze/wbge2c72nv ep5a 0 j zgw4q -)8n

A. work.

B. kinetic energy.

C. power.

D. potential energy.

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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 vkc)g4m;wn5if is 9sa1s. x), what represents the work done by the force F?kafw5);ni s1 4s 9gmic

A. the slope of the curve

B. the length of the curve

C. the area under the curve

D. the product of the maximum force times the maximum x

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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

A. the kinetic energy of the object.

B. the potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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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 posifu cer7 36 n,ob+.oacbtive, then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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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 negative, then t2;f hihk/d3u5.*axsf 1b d qaihe object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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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 zdpfnoo a; d-o .,)o:uobject's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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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 twict s xpqol2 d35.yv6e t0nbvv 3f91c3kve the speed of the car. Which statement is true about t6d 3 f1vvq nce20 ktpbl3t9y vs.v35xohe truck's kinetic energy compared to that of the car?

A. All that can be said is that the truck has more kinetic energy.

B. The truck has twice the kinetic energy of the car.

C. The truck has 4 times the kinetic energy of the car.

D. The truck has 8 times the kinetic energy of the 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 fas cdozobftt .5d(kw3*w4z(qt stff*( :t as car K, and car J has half the mass of car K. The kinetic energ(*dzffswt:tq(td*5 wb. tck(f4 3oz oy of car J, compared to car K is

A. the same.

B. 2 to 1.

C. 4 to 1.

D. 1 to 2.

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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 wall6zul.8em nxlgu9 )e v0 and bounces back with half of its original speed. What is the rati 0n. l69evul )8umgxezo of the final kinetic energy to the initial kinetic energy?

A. \frac{1}{2} \;

B. 1/4

C. 2

D. 4

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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 y 3)ei1-hsgqk y q*c*zand a pebble is moving at a speed of 5 m/s. If both obj3syq)q g**e iz1y-hkc ects have the same kinetic energy, what is the ratio of the brick's mass to the rock's mass?

A. 25 to 9

B. 5 to 3

C. 12.5 to 4.5

D. 3 to 5

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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 is mn;v ctmnn964k+ khs9 woving with speed 4.0 m/s. Both objects encounter the same constant brakics n4+t9mkvk ;n9 h6wnng force, and are brought to rest. Which object travels the greater distance before stopping?

A. the 4.0-kg mass

B. the 1.0-kg mass

C. Both travel the same distance.

D. cannot be determined from the information given

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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 car in a panic, and skid a certai6ls,cm06 ( vc;adyoo zyyw6agd t,*m7 n distance on a straigytlad;ms g(yvooz6y 7md *,cac 660w,ht, level road. If you had been traveling twice as fast, what distance would the car have skidded, under the same conditions?

A. It would have skidded 4 times farther.

B. It would have skidded twice as far.

C. It would have skidded 1.4 times farther.

D. It is impossible to tell from the information given.

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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 orbits the Sun in an elliptical o *e:s-vf :xqnwrbit. Neglecting any friction effects, what happens to the planet's kinetic enfv*-:xn: w eqsergy?

A. It remains constant.

B. It increases continually.

C. It decreases continually.

D. It increases when the planet approaches the Sun, and decreases when it moves farther away.

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22#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the work-energo0x90xxqc4xq wtc+f7zk(s/ nbk i4c,f e 0pz*y principle.

该题自我估分: (必填) (满分:1.0分)

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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

A. the kinetic energy of the object.

B. the gravitational potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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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

A. the kinetic energy of the object.

B. the elastic potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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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 negativrlb hab5 b -2i20fknzg u1ir5)e potential energy?

A. Yes, as long as the total energy is positive.

B. Yes, since the choice of the zero of potential energy is arbitrary.

C. No, because the kinetic energy of a system must equal its potential energy.

D. No, because this would have no physical meaning.

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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 reln;jcv0 , q.vnay. /iost 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 c/a..0; qi ncjnv lv,oyompared to the first is

A. one-fourth as much.

B. one-half as much.

C. twice as much.

D. four times as much.

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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 causes it to stretch 5.(5yvi *vet4wuf/ sp56z uf- 1fkied,q0 cm. If another 0.fp-if *4k5/stvwufue 6,de (yiv5 z q1200-kg mass is added to the spring, the potential energy of the spring will be

A. the same.

B. twice as much.

C. 3 times as much.

D. 4 times as much.

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28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The total mechanical enenuguo )pv a :oo8g6.-krgy of a system

A. is equally divided between kinetic energy and potential energy.

B. is either all kinetic energy or all potential energy, at any one instant.

C. can never be negative.

D. is constant, only if conservative forces act.

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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 tree. Compare its kinetic energy K,bs y88*s( xvob to its potential energy U. 8 s(bbvox*8sy

A. K increases and U decreases.

B. K decreases and U decreases.

C. K increases and U increases.

D. K decreases and U increases.

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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 c j7zm5z2jhf(yp b1pc6ar driving up a hill.

A. entirely kinetic

B. entirely potential

C. both kinetic and potential

D. gravitational

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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 a very heavy objectpa8xnl v)c-v,m :s. yp are sliding with equal speeds along a level frictionless s cp sm,a.8xvp:ynl v)-urface. They both slide up the same frictionless hill. Which rises to a greater height?

A. The heavy object, because it has greater kinetic energy.

B. The lightweight object, because it weighs less.

C. They both slide to the same height.

D. cannot be determined from the information given

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32#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Consider two masses duf-8ga :,r) jk 5qgdu$m_{1}$ 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?

A. $m_{1}$

B. $m_{2}$

C. They both are going the same speed.

D. cannot be determined without knowing the masses

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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 conservative forlll ;4jisd5l5um6 mq am) -cy5cesm4 jl -qmid cslm556)lu5ay;l.

该题自我估分: (必填) (满分:1.0分)

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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,5yh /3qyz/e bn through the air (air friction is present), to the ground below. How does the kinetic energy (K) just before striking the ground compare to the potential energy (U) at the top of the buildyh qn/53ybz/ eing?

A. K is equal to U.

B. K is greater than U.

C. K is less than U.

D. It is impossible to tell.

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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 energyldq8m 8yrk:a:t e d5y id3p9l7. Do not ignore air resistance. How much gravitational potential energy tp7e :93: mk 8aqlrdddy5 yi8ldid the ball lose?

A. more than 30 J

B. exactly 30 J

C. less than 30 J

D. cannot be determined from the information given

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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 gravitational potential energy. Do5u rbmum*.j/g not ignore air resisug*j.mumb r/5 tance. How much kinetic energy did the ball gain?

A. more than 30 J

B. exactly 30 J

C. less than 30 J

D. cannot be determined from the information given

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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 conservation of eneo2vw x0xe6.xau,nr 5argy.

该题自我估分: (必填) (满分:1.0分)

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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 isoj5 :zz6oqy zl2*gwxq+2hpc+

A. the kinetic energy of the object.

B. the potential energy of the object.

C. the work done on the object by the force.

D. the power supplied to the object by the force.

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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 expressed in ) r01mspwfus,kt3 n;c dx-t4d(fcc)i SI units?

A. $kg m/s^2$

B. $kg m^{2}/s^2$

C. $kg m^{2}/s^3$

D. $kg^2 m/s^2$

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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 not a unit 4b8sls0f:acbgdev n+/ru;. i of power?

A. watt/second

B. newton-meter/second

C. joule/second

D. watt

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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 on/ugg45. khv s0;m hbiwe-third the time. To do so, your power output5 bg/hum.0 kwhvs;4gi must have been

A. the same as yesterday's power output.

B. one-third of yesterday's power output.

C. 3 times yesterday's power output.

D. 9 times yesterday's power output.

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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 acceleration, the crc) . l1e0xiaqar's engine must

A. maintain a constant power output.

B. develop ever-decreasing power.

C. develop ever-increasing power.

D. maintain a constant turning speed.

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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 andn t6b29ulc0ul held there. If the object weighs 90 N, 09bllu26 ucnthow much work was done in lifting it?

A. $360 \; J$

B. $180 \; J$

C. $90 \; J$

D. $0 \; J$

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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 the air a distance of 1.0 m, a+9v mb (sz.ar+scudy 7t a constant velocmvz +sa.y(s rbc+d9u7ity of 0.50 m/s. What is the work done by the weight of the book?

A. +10 J

B. -10 J

C. +5.0 J

D. -5.0 J

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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 yjctvlhhg 4gbvbcu3r 748gta.1599 wa constant force of 5500 N for a distance of 50.0 m. What is the work done by the 5500 N fvbhc9a38y h7tbjrgl 9g441wg.5 uctvorce?

A. $2.75 \times 10^{5} \; J$

B. $-2.45 \times 10^{5} \; J$

C. $3.00 \times 10^{4} \; J$

D. $-5.20 \times 10^{5} \; J$

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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 const 5x *nni-*t:vwmg9mbk a+vc )bant force of 5500 N for a distance of 50.0 b+x9*gkc: imn t-vwb nav5*)m m. What is the work done by the weight of the elevator?

A. $2.75 \times 10^{5} \; J$

B. $-2.45 \times 10^{5} \; J$

C. $3.00 \times 10^{4} \; J$

D. $-5.20 \times 10^{5} \; J$

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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 upward with a constant force of 7cx p)q) h2pxc(r-8 6 g4irpma-o;*ohtke ren5500 N for a distance of 50.0 m. What is the n 4)aonrrt 2g hmc86(ko r ;x-7-ipxeeqp*h)cp et work done on the elevator?

A. $2.75 \times 10^{5} \; J$

B. $-2.45 \times 10^{5} \; J$

C. $3.00 \times 10^{4} \; J$

D. $-5.20 \times 10^{5} \; J$

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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 m up along ykrlr12 m zv+)2j+ffma $37^{\circ}$ inclined plane. What is the work done by the weight (gravitational force) of the box?

A. $-11 \; J$

B. $-1.1 \times 10^{2} \; J$

C. $-1.4 \times 10^{2} \; J$

D. $-1.8 \times 10^{2} \; J$

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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 8.0 m down a ramp, i)ot iewmp0 w*qnm23n )nclined 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?

A. $157 \; J$

B. $-157 \; J + 78.4 \; J$

C. $78.4 \; J$

D. $-78.4 \; J$

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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 siste.wokdka58dh29z 6 myfg tx4t51 hhco.r Sarah in a sled on an icy surface (assume no friction), with a force of 60.0.6xydwo m 4h.o k5c92g5t kthadhz8f1 N at an angle of $37^{\circ}$ upward from the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew?

A. $185 \; J$

B. $433 \; J$

C. $575 \; J$

D. $720 \; J$

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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 t,iu8n 32(b; mnwjuc(ebf.u fdhe direction of the force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object movesuf2cdemnu( b(.,;fn3bi8 jwu from 0 to 2.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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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 es5 8jr6*7x qs.islso1 d)hdydirection of the force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object qr 7)x .ih6jds oe8ss*yld51s moves from 2.0 to 4.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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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 direcx.( (dd7gbr:zuyds 19c z ahg3tion of the force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done wg1z 9c.auybrsg:7dh d zd3(( xhen the object moves from 4.0 to 6.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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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 directpm:rroy,: m+; rgn 1qpion 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 6: y:n+q, ;gor1prm prm.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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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 move a 55-kg cart (initially at z iuld)2 :p8 vij;w0dgrest) across a 10 m leve:0g2d wi8 u) ipzjld;vl surface. What is the final kinetic energy of the cart?

A. $1.0 \times 10^{3} \; J$

B. $2.0 \times 10^{3} \; J$

C. $2.7 \times 10^{3} \; J$

D. $4.0 \times 10^{3} \; J$

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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 mov) jiu/)a past-e a 55-kg cart (initially at rest) acrost js-ip) aa/u)s a 10 m level surface. What is the final speed of the cart?

A. 73 m/s

B. 36 m/s

C. 8.5 m/s

D. 6.0 m/s

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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 speed of 5.0 m/s. Howx +oy,nh(-nw h much work is required to stop the+ (n, y-hxnhow mass?

A. $50 \; J$

B. $75 \; J$

C. $100 \; J$

D. $125 \; J$

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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 17f u 7b+wqp0ymcym.7o8 ixqvstop a car initially moving at 25 m/s, what distance is required to stop a car moving at 50 m/s under the same condition oq1x7bp8mi fwqu yyv7c.7m0 +?

A. $50 \; m$

B. $100 \; m$

C. $200 \; m$

D. $400 \; m$

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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-v yu cbo*g**f*6us-k pg dart. It is cocked by exerting a force of 20 N ove*f v-6ug*b**ucpy ksor a distance of 5.0 cm. With what speed will the dart leave the gun, assuming the spring has negligible mass?

A. 10 m/s

B. 14 m/s

C. 17 m/s

D. 20 m/s

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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 componentf:w h peel7.)zn)b, cgob 1:bm of 80 N and a vertical component of 60 N. The 1z7,emhnwbec)l )f p obb :g:.force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2.0 m horizontally along the floor. What is the cart's final kinetic energy?

A. $200 \; J$

B. $160 \; J$

C. $120 \; J$

D. zero

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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 oftzj g/wg4h p8wft6nz0j)c))s hay, striking the hay with a velocity of 60 m/s. It penetratggpzz6jf/wh0 j n)8 sw) t4)tces a depth of 20 cm before stopping. What is the average stopping force acting on the arrow?

A. $45 \; N$

B. $90 \; N$

C. $180 \; N$

D. $360 \; N$

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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 m above a floor to a height of 1ybe7aswx . d(23.0 m abovebx7( w.aed y2s the floor. What is the change in gravitational potential energy?

A. zero

B. 1030 J

C. 1176 J

D. 1910 J

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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 4.0b6 sgw+nf7yq ,8mme)x m long and rises 2.0 m. If the plane is frictionless, how much work was done by the p+x yne )6,g7qwsb8 mfmush?

A. $1600 \; J$

B. $800 \; J$

C. $400 \; J$

D. $100 \; J$

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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 spring to stretch 2.0 cm. Whi bwb:j vay;xt1prx4yygi,*1+ :las /1gplr4 at is the spring c s1/1:rai*4 jvyx,y ila ;b4wrp1b l+:gpg ytxonstant?

A. $4.9 \times 10^{3} \; N/m$

B. $5.0 \times 10^{3} \; N/m$

C. 20 N/m

D. 2.0 N/m

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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 9 pz:qr+ r7lpja spring constant of 60 N/m. How much potential energy does it store, when rjq9rl p+:zp 7stretched by 1.0 cm?

A. $3.0 \times 10^{-3} \; J$

B. $0.30 \; J$

C. $60 \; J$

D. $600 \; J$

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66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Calculate the work required to compress a;a8 n50wlrt6 i6waxdh n initially uncompressed spring with a a86id6;5 wwnaxlt0 hrspring constant of 25 N/m by 10 cm.

A. $0.10 \; J$

B. $0.13 \; J$

C. $0.17 \; J$

D. $0.25 \; J$

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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 spring constantgnq i./t0o 7 onoj:i*z 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretched position is at x = 0z/*qj7:gtion .i oon0.)

A. $0.45 \; J$

B. $0.80 \; J$

C. $1.3 \; J$

D. $0.050 \; J$

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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 constanv lna8e9+,wmazz :u- 8f4usskt of 15 N/m is initially compressed by 3.0 cm. Howf-:uvs m z4u+8sa8z9nwa e,lk much work is required to compress the spring an additional 4.0 cm?

A. $0.0068 \; J$

B. $0.012 \; J$

C. $0.024 \; J$

D. $0.030 \; J$

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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 f9q u :3ir40wusl zxkd6rom the top of a 50-m high slope. What is the speed of the skier on reaching the bottom of the slope? (neglect fru60ikl d:wrsxu z 49q3iction)

A. 22 m/s

B. 31 m/s

C. 38 m/s

D. 41 m/s

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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, pushee/dsdxe,ibydv n91 j11me)gg6u +4 lps off the top of a hill with an initial speed of 4.0 m/s. Neglecting friction, how faegnmp,g 91 d1eyj6)vd dxl4+bi s/1 eust will she be moving after dropping 10 m in elevation?

A. 7.3 m/s

B. 15 m/s

C. 49 m/s

D. 196 m/s

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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 frictionless inclined plan ebj l w2v+amc 0m2x1w5jom1s1e. At the bottom, it has a sp1ve js+j1cwla2omx0bm2 1m w5eed of 9.80 m/s. What is the vertical height of the plane?

A. $19.6 \; m$

B. $9.80 \; m$

C. $4.90 \; m$

D. $2.45 \; m$

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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 s jd32jnisj6wl ou8.3 it is 0.70 m above the floor, its potential energy exactly equals its kinetic enesjund32 l8wo.sijj63 rgy. How fast is it moving?

A. 3.7 m/s

B. 6.9 m/s

C. 14 m/s

D. 45 m/s

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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 grounbedo2oz 6fba 812zc0q d level with a kinetic energy of 40 J. At the exact top of its trajectory, it8qeobcfa16zd2b 2 z o0s total mechanical energy is 140 J. To what vertical height does it rise?

A. $1.0 \; m$

B. $10 \; m$

C. $14 \; m$

D. $24 \; m$

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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 grou92ycdhc3na: 7 rm0xcknd 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 podcr3a cc:n hx027mk y9int, did it rise?

A. $\frac{220}{mg} \; m$

B. $\frac{120}{mg} \; m$

C. $\frac{100}{mg} \; m$

D. Impossible to determine without knowing the angle of launch

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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 point 45 m above the bottom of)9b d,elmuxk/z,9d m fb0hv8y a dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slvxbb9)lf8k /ud, hy9 m0m d,zeope, which is 30 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 17 m/s

C. 24 m/s

D. 30 m/s

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76#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster starts with alyubv47h8 bhz.t( o 2w 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 at the top of the next slope, which is 30 m above the bottov(y 2zwl7 .h8t4ub bhom of the dip?

本题所包含的其它图片:

A. 12 m/s

B. 14 m/s

C. 16 m/s

D. 18 m/s

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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- bvlr2/jr hw cl1u7-u-n6ba c bottom of a dip with a speed of 25 m/s (See Fig. 6-2). Neglect frictionr-6v-ub1c2lhbj/ rluwan c- 7 , 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?

本题所包含的其它图片:

A. 14 m/s

B. 16 m/s

C. 18 m/s

D. 20 m/s

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78#

( 1.0 分) 切至整卷模式搜藏此题

What is the minimum spe5 p 2 5-du:ecurr t(xwhc2fn6sed of the ball at the bottom 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

A. 3.1 m/s

B. 4.4 m/s

C. 4.9 m/s

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80#

( 1.0 分) 切至整卷模式搜藏此题

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 2-kg pendulum of length 50 cm is pulled 0.15 m away from the vertical ax4d63m v( armopis and released from rest. What will be its speed at the bottom of its r pv4(dmam o63swing?

A. 0.2016 m/s

B. 0.538 m/s

C. 0.806 m/s

D. 0.672 m/s

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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 uncompressed horizontax4o-qqzxa sr+ *8am g. wa)l;kl spring with spring c k)8;a qo4a-s z.w qxlamgxr+*onstant of $2.0 \times 10^6 \; N/m$. What is the maximum compression of the spring? (Neglect the mass of the spring.)

A. $0.17 \; m$

B. $0.34 \; m$

C. $0.51 \; m$

D. $0.68 \; m$

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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 20006ezy7sd:es)ytjq ,6 x kg car to stop for a red light. What work is)7je66qydtzsx se: ,y done by the friction force against the wheels?

A. $-2.2 \times 10^{4} \; J$

B. $-4.4 \times 10^{4} \; J$

C. $-4.84 \times 10^{5} \; J$

D. $-9.68 \times 10^{5} \; J$

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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 horizontal surface kte +(hrwf,9w:.z nah is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slia+k w. en:wh,h(rf z9tde before coming to a stop?

A. $15.0 \; m$

B. $30.0 \; m$

C. $375 \; m$

D. $750 \; m$

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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 on a roughl ,u m/y3otwr 3a:ycd;8r1ukf.zs nv., level surface. It has 24 J of kinetic energy. The friction force on it is a constant 0.50 N. How far will it s:.dy l m8ork,/w.uya snvurzc1 tf3;3lide?

A. $2.0 \; m$

B. $12 \; m$

C. $24 \; m$

D. $48 \; m$

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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 mass 26g 3ypskqsq)84yct mq*oks( on a level surface. The coefficient of kinetiyst*q83( )csp4qo6s m kg2k qyc friction between the mass and the surface is 0.20. If the mass is moved a distance of 10 m, what is the change in its kinetic energy?

A. $20 \; J$

B. $39 \; J$

C. $46 \; J$

D. $61 \; J$

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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 slopno ;1ek81c whie. If the work done by fk8newo ;hi 1c1riction 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 up an inclined plane. The pla6op,idc gc-2l7b; lam db2f6cne is 4.0 m long and rises 2.0 m. It requires 3200 J of work to get the box to the top of the plane. What was the mfo b cacpmldg,dbl6 6; -2ic27agnitude of the average friction force on the box?

A. $0 \; N$

B. non-zero, but less than 400 N

C. $400 \; N$

D. greater than 400 N

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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 inclin 9v6bft:2pl6l f(z nrpuiv:ee:* gzu/ed at 20e above horizontal. The coefficient of kinetic friction between the l 2 6l:*/uzg9ref vpnze:tpi fuv(6: bmass and the plane is 0.20. What will be the speed of the mass after sliding 4.0 m along the plane?

A. 2.2 m/s

B. 3.0 m/s

C. 3.5 m/s

D. 5.2 m/s

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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 dropped from a height +h34kqlpt3klp. e9 xyof 10.0 m, and strikes the ground with a velocity of 7.00 m/s. What average force x 3+9ktyl.3 lqpe4ph kof air friction acts on it as it falls?

A. $22.5 \; N$

B. $75.0 \; N$

C. $225 \; N$

D. $293 \; N$

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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 60.0-kg boy using ener, w060ga r2e kcmzuvvl8 :i7by/f (qlvgy when he runs up a flight of stairs 10.0-m highry2,v /e z(qvw: 6u8bmc lfi0kg07 lav, in
8.00 s?

A. $75.0 \; W$

B. $735 \; W$

C. $4.80 \; kW$

D. $48 \; W$

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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 to13/ lyql eeeo. move an object with a constant velocity of 5.0 m/s. What powery1le3 /eloq. e must be delivered to the object by the force?

A. $0.50 \; W$

B. $1.0 \; W$

C. $50 \; W$

D. $100 \; W$

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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 motor that runs for 1.0 hr? (18dd,s, duufx 1 hp = 7 ,ds, 8xdud1uf46 W)

A. $3.6 \times 10^{3} \; J$

B. $2.7 \times 10^{6} \; J$

C. $4.5 \times 10^{4} \; J$

D. $4.8 \; J$

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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 ratet cz6)yh x0whs(5df:h of 500 W while riding. How much force does her foot push with when she is traveling at 8 h6hcw0 xtz hd()f5y:s.0 m/s?

A. $31 \; N$

B. $63 \; N$

C. $80 \; N$

D. $4000 \; N$

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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 accelerates frfjv o6l:t,;:g hln6i6v 7ynggom 0 to 25 m/s in 7.0 s. What is the average power delivered by the engi,nv t76;lgg 6in:j ly:6hofvg ne? (1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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