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

1#

What is the correct unit of work expressed in SI un q5; z: tfb8v 9rw4ha,8enzzpcits?

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 s+k2 an.iwf, igystem if there 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 o be5 q05qj, bqcw,,+xpvszwg. f work you d ,q,q+ bc0ws 5jvqw, e.b5pgzxo

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 beimizt: h5)q: 0deqf7qeng held there. How much work qe :dq)qtih5:me f z70is 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 forward at a cow ts5k( ucc j: t ksr4j1z l/81r9ps2,op*jrtxnstant velocity carrying a 10-N object, the amoun1k5p4crojct:jr,r1ls(ws 9t8sj* kxp 2tz/ut 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 then returvj;k/c2c mh rs5pj bni-/*e1hned to its original position. If the total weight is 30 / 1/2;j5-cpki h cemjrbnvsh*N, how much 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 on an object do work on thjqjq3d. + ;slje 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. Compar(d w:h2 qryl)85tt 7lx5dege se the sign of the work done by gravity while the ball goes up with the sign of the work done by gravity while it goes doewg shel7: tl5 rtx8(d )5dy2qwn.

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 position (F vs. x) graph, represen0gsow,m ui( 6gbke1;r ts s1mre 0(g;bgui,wk6o

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 vs. x), what represents the a:t.k*;)m , e;ar yk8fnhxaatwork done by the fork; km h)yrt.:ae,*;8a t nxaafce F?

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 positive, then the objectv 01gyke(qju87 s7 dxh'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 donecv- 2vam5 darkpf8lx4 f0 l-h6 on an object is negative, then the 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 tb: b9cx hy6wzoe*gjpg 3lj:6lug+* 7yhe object'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 twice the spee)pj8w7x 4/x+ yjlof eed of the car. Which statement is true about the trwe7jyx8 f +x) /pe4joluck'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 fast as car K, and car J has half the mass of caie.o 6/o kmm5br K. The kinetic energy of caieko .5bmmo /6r 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 wall and bouncez yrq(wzx(5 ctf6uf2/s back with half of its original speed. What is the ratio of the final kinetic energy to the fx 2 zc(yf/5tzq(uw6rinitial 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 and a pebbleb65kj7fosfwu 7+) ujr is moving at a speed of 5 m/s. If both objects have the same kinetic energy, what is t+jr6ojf u7 bwu)7 fs5khe 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 wl jhc2e v69 xx sl(ju*vm/*4q2.0 m/s. A 1.0-kg mass is moving with speed 4.0 m/s. Both objects encounter t9 vj6lc*xv qw/ ul2j4m(hsex*he same constant braking 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 ac a4xlmn*7n+ vpsk3*certain distance on a straight, level road. If you had been traveling twice as fast, what distance would the car have skidded, under the same condi v7x4nn k+pac*salm3 *tions?

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 orbit. Neglects 0i/tragcbmw,f 8)w1ing any friction effectbc8s r,i10afmwgt/) w s, what happens to the planet's kinetic energy?

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-energy pritpu(9g+ht rf3nciple.

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 hav-,/bryewosxe, ,oeb0e negative 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 rest a height h above the grouuix3d8:e h e+a 3ln,+.osvjsand. A second object with four times the mass of the first if relea+j h .ioeva3 ,u8 xlne:3ssd+ased from the same height. The potential energy of the second object compared 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 spri 0r qk5m0efuo)4di 9 d9rmlsj9d w3j*bng causes it to stretch 5.0 cm. If another 0.200-kg mass is added to the spring, the potential energy ofmfwl9jd ioq rj*)dm00r 3edksu99b45 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 end- xb3p ots4y. c,5bc.xhgv2tergy 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 kinet2 +gvq9fen : agkj2hi7ic energy K, to its potential eneri gvh :gefjn+9a 722qkgy U.

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 car driving up a hcv wevp f5avk t-mi/2d)4+qj*ill.

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 object are sliding with equal speeds along* * zx4im gm4ozqm4q9w a level frictionless surface. They both slide up the same frictionless hill. Which rises to a greater h4xgmw *oz *mzqq9i4 m4eight?

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 0xr /a.qzfy9v$m_{1}$ 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 conservatv0;8g j sffo0wive forces.osg0w8 ;jvf0f

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,4 tu jsfb5t*1o 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 ooj*1u5t t4fs bf the building?

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 gai;nhs zmkp(l nk7*+7td3a mxrpy5,r( tns 30 J of kinetic energy. Do not ignore air resistance. How much gra7rt m7 npz*dr3la+n5( p tkh;,ys x(mkvitational potential energy did 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 gravitatiokyz c7hp xvwk/r ;z og ex80;+jt/-l2unal potential energy. Do not ignore ailv2jgc;/yukx+w zhk7po xr t-08z;/ er resistance. 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 conservatiop zp nnr(nnr*-r:y (vc .aba79n of energy.

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 isp4dnkc*1qib 1 j3i g)z

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 pht-yr u 6oe4l,ower expressed in 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 o.rd*6ekax5u 8 n8sf k,py w5aunit 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 s7c h d(t)ogd+the work in one-third the time. To do so, ygodh d( +sc)7tour power output 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 qp)7(5yre:7 qoor kiaa constant acceleration, the car'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 and held there. If the o /lzq6e*l gcv c+5tfh,bject weighs 90 N, how mz +evl* lcgq,6fh/5ctuch 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 disef.kse5-e.q htjj 2g2 z:eo8qtance of 1.0 m, at a constant velocity of 0.50 m/s. What iso 2eq .eeejkzh-gsq:j .tf528 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 , s(rux; bn4tgwith a constant force of 5500 N for a distance of 50.0 m. b g,tr(nxu ;s4What is the work done by the 5500 N force?

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 w3-.k-,bydvs g,2rit ip kdf9zith a constant force of 5500 N for a distance of 50.0 m. What is the work done bi pd.tb zky3,rf9g--i d vs2,ky 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 550 +nt(b9lx*qxdmun; /k0 N for a distance of 50.0 m. What is the net work donen*xm klux;t nb (9/+dq 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 6ty4k b:ybx/q2k;e8 t(n+rrr m,sfkf9.0 m up along a $37^{\circ}$ 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 8p; *zl yvmyft,)ba0;s.0 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?

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 sister Sarah in a sled on q1vv1pd1ecm(hx2s/k an icy surface (assume no fricti/q1 dm11e2( kshvvcp xon), with a force of 60.0 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 the direction of the forcb :dj r*m/l2hpn+uel, e. The graph in Fig. 6-1 shows the force vers:2rbhluld* + m,je/ pnus the object's position. Find the work done when the object moves 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 direction of the forceo+im j:v 6s,umy-x;j k h+;q (8etytxw. The graph in Fig. 6-1 shj;y- 6:wymtmq u+t(ks x 8o;hx,e +jivows the force versus the object's position. Find the work done when the object 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 direction of the force. The graph in Fig. 6-1 s*zp, e )ig6 s9wwpdr0bhows the force versus the object's position. Find the work done when the0 9erpw6sipw )d*bg,z 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 direction of the nkjtqq:i/ri5+e0r9 tforce. The graph in Fig. 6-1 shows the force versus the object's position. Find the work 0t r9qt ki/j+5i:rnqe done when the object moves from 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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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 v/)e2;na(bciz hwpn/ to move a 55-kg cart (initially at rest) across a 10 m level surface. h)pe/i(wn/2av z;bcn 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 move a 55-kg cart (initially at rest :ozh/sv *kh 7hu6osu5) across a 10 m lzh*o 7 :vh65h /sosukuevel 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. Howzdglii.9l 77q much work is required to stop 7 l9iz li7.gdqthe 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 stop a car initially mncu/2lvt. wk g8.y84 cvqg 7/k+/e1g byyvzf moving at 25 m/s, what distance is required to stop a car moving at 50 m/s under tcev/8g1wy/42c m yy7u+ngl 8zvk.fktvg / .bqhe same condition?

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-g dart. It is cocked sc y-:* 8gqmuhby 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:q *sh-m8gyc u 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 hor5sw *.yp 4 na9c,vnhrhizontal component of 80 N and a vertical component of 60 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2na4nhvw*,s 9c5pry . h.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 saghkczg+rr cc,)n jj9)0 o:)is shot horizontally into a bale of hay, striking the hay with a velocity of 60 m/s. It penetrates a depth of 20 cm before stohr+ c ))9),k:jo 0c arncgzsgjpping. 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 ht5gm-3ef in9x- wz ef/4lk :dqeight of 7.00 m above a floor to a height of 13.0 m above the floor. What is t -gf fe3:dixemn94kz/-tw5lq he 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 ish dj.wj,gmq16gr*+xm a 73zx s 4.0 m long and rises 2.0 m. 7sax m x+ ,wr.h1*6jd3mgj zqgIf the plane is frictionless, how much work was done by the push?

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. What i p9egcwbm z cc/y)a.4x.g3jl8s the abgec4 cx.z. g3 cm/l)p9 8jwyspring constant?

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 a spring constafdbh):urg7yn /xs:/wk a x +8qnt of 60 N/m. How much potential energy dou wf )d/kh7s+b:grnxya8q: x/es it store, when stretched 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 an initially un x2zdo xw-y:4u an-kmrz kto( u.+a7u.compressed spring with a spring constant of 25 N/mxx+4 ud2zo. w(zyk:mk 7n-.uu aort-a 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 constant 40 q10m0jd( z3n0fajz5 cm t1ypj4bue1 yN/m from x = 0.20 m to 0.25 m? (Assume the unstretched pod ct0j3z n yqj(p0514ue1zmj10b ymfasition is at x = 0.)

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 constant of 15 N/m is i ,//e*kyuskn hv*o b) q8.jbotnitially compressed by 3.0 cm. How much wok*b/huyv8 ,q)t/.* kejn obsork 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 frj- wd:7: gomi7z ye)lxom the top of a 50-m high slope. What is the sp7 glew: ox-d7)yj :mzieed of the slier on reaching the bottom of the slope? (Neglect friction.)

A. 22 m/s

B. 31 m/s

C. 9.8 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, pushes off the top of a hill with an initia)8hq co840z(ii qu62rujo(b wqr k +wxl speed of 4.0 m/s. Neglecting friction, how fast will she be moving after dropruw(4o)(b oi8rq zikqjq xc h2+0u68wping 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 in* yb;rht + (+ ot6yxc.dmkylf1clined plane. At the bottom, it has a speed of 9.80 m/s. What is the vertical height of the rhm1ko y .++xydt (6byf *c;ltplane?

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 it is 0.70 m above the floor, its potakxsz4rh sx jyjlo --h-p1j*h18y 72p ential energy exactl jxylr-y4pk*1z-h2 8ja 1xjshs- hp7oy equals its kinetic energy. 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, bsc*l*(fs7ojt 2uu a5/on muv5sl n7;f7mcs y5 lasts straight up from ground level with a kinetic energy of 40 J. At the exact top of its tr5slmfjsn(* 7suclou5*y/5 v ou7 ;nc2st fa7 majectory, its 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 ground with a k8kadddr4 a ua6:u,5qif4y y0 ginetic energy of 220 J. At the highest point in its trajectory, its kinetic energy isd5 a0yfqkg6aduaur, :4y 8i4 d 120 J. To what vertical height, relative to its launch point, 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 a dip (Se,0;rqtww zu; be Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the ;wqzu r,w;t0b top of the next slope, 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 a speed of 5.0 m/s at a p0po+-vwvglgy( - bht 4d8 tk558sazufoint 45 m above the bottom of a dip of tdwyb-85gk0-4s+8tvvu gap( 5lzh(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 bottom 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 bottom of a d3ja nl3 *v1h;8 yo:w7fresv pch i7yl.ip with a speed of 25 m/s (See Fig. 6-2). Neglect friction, what wi71 avfe.lip hrw7y:3 hn *oj38l vcy;sll 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 speed of the ball at the bottom of its swing (m kw 0;ic 0:u8dqztkhm1 2njl+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 pendulum of length 50 cm is pulled 30 cm away from the verti.d3 :tcxyk ip)cal axis and released from rest. What will be its speed at the botyi .c3tp: xk)dtom of its swing?

A. 0.50 m/s

B. 0.79 m/s

C. 1.2 m/s

D. 1.4 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 adro97a0u + surx7ugvlibc51 +t 25 m/s hits an initially uncompressed horizontal spring with spring conrsi+1 xc7+59ulbv ar oudu07gstant 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 05lbh2pya6ezy 8 fle -her 2000 kg car to stop for a red light. What work is done by the friction fo0 f52 hplayez-68l eybrce 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 horizon-yrlj e 2p-ww/tal surface is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slide before yr/w-ej w2 lp-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 rough, level surface. It h2e r zd.mx dqr97c;d3hcl2(xbq i ht85as 24 J of kinetic energy. The fdzhrr 2e q 8c(xc3dm5.2ixlq97hbt d ;riction force on it is a constant 0.50 N. How far will it slide?

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 on a level suje7r)r7j k4)yc/zf 7, qdk g/dpc6ihbrface. The coeffic6 fjp)/),dirdrg 74 kjc77kyqbhze/ cient of kinetic 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 the5fqup2t6 gw6f0l )0bqamd; xlw4 f:qt top of a 50-m high slope. If the work done by frictionl;60fx b)qgmw4q0:5fp f6qua tlt2 wd is $-6.0 \times 10^{3} \; J$, what is the speed of the skier on reaching the bottom of the slope?

A. 17 m/s

B. 24 m/s

C. 34 m/s

D. 31 m/s

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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 plane is 4.0 mc2y t4:qdoda 7 long and rises 2.0 m. It requires 3200 J of work to get the box t7y: d d24tcaoqo the top of the plane. What was the magnitude 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 lt33+9n(a qd os 7fghyfrom rest at the top of a plane inclined at 20e above horizontal. The coeffiatlg n3+y3sfh 7d9(oqcient of kinetic friction between the mass 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 of 10.0 m, and strikes the ground w9to gjbg9c5t m;aew-9se3 jzevt*5 3qith a velocity of 7.00 m/s. What average force of air frict-vt gt5*ozgb j93jcaqt9;we se5em3 9 ion 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 energy when he runs up a flight of4dzb,;bf)p bx:/v5w3 xs mxuq stairs 10.0-m high5 d,uq4zx3p/s:)b vxbb mfx;w, 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 to move o ut6-5 ic paswm49rw20vk3mr an object with a constant velocity of 5.0 m/s. What power must be delivered to the object4m ows60am 5wk-vt923up ricr 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.o4qi1+y6imfozq m; -v q9 .oss0 hp motor that runs for 1.0 hr? (1 hp 4y+ v9.s1ozm osq6mqi-qo f;i= 746 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 rate of 500 W vi.)1yodj/w lwhile riding. How much force does her foot push with when she is traveling at 8.0 m1wovi j/).y dl/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 from 0 to 25o-( 9usps8qg1 k-p2ajht 3neix2u hj4 m/s in 7.0 s. What is the average power delitan8pij ( -p- jske9uquxgho12s3h 42vered by the engine? (1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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