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

1#

What is the correct unit of work exprespq8 ((4juhgb8zz pb e2sed 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 there is no motbn y5 e;wr6plcsz7,6de vm6v) ion?

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 of worm ex; zadgm2p95t8x 0yk you dpmyed02z5xg9t8 x;m a o

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 there. Hojg ak, n/dkew)k3 nq:*w much work is being done in holding the box in twkekjn/qn a: )dk3 g,*his 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 constant velocity d * .p)xjp-ksycarrying a 10-N object, the amou.)jppdy -s*x knt 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 06mpbzdai 8o8/fk bk; /po* v +5iwjmn3.0 m then returned to its original position. If the tot 0bapo8* m/wjp ndvif8/i5z+6;m ob kkal weight is 30 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 act)5st jhlj q9-e-g2 i/ t(djipuing on 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 the sign of the work done y.y;m9po tvwblds58n) 4.j li by gravity while the ball goes up with the sign of tj )59nmyy.; ltpl4bivd os8. whe work 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 position (F vs. x9k+s* 12w( 6ii hsvesz-nehnf) graph, representseks6*1n n9wh vessf 2-ii+z(h

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 q) ;n7 pxlg,hyn :hyq3position (F vs. x), what represents the work done by the force F?yn;q)3:h h7lg pnqyx,

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 vdluy5wo7iygs 6n4 3: 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 the object's kinetic enetu )6 vcccj7 f/vmy/2ergy

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 ze (e.anpho-r3- g7toy :5k zodwy3g8v(z yi wc5ro, then the 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,/obm0 ((4e g3ycywii e and is moving at twice the speed of the car. Which statement is true about the truc0ieew(o(4y / bc3giym k'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 as9:qn by0zoy qzg9n e)zebyfd4: y1j*7 fast as car K, and car J has half the mass of car K. The kinetic energy of09* b4z qee )oq: z:71bfyygj dy9yznn 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 wall and bounces back with half of its original speed. Wb c4n wj:qy88fhat is the ratio of the final kinetic energy to the jn:fq8y 4w8cb 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 and a pebble is ppy(+sqo/w* r moving at a speed of 5 m/s. If both oy+qpr*s (opw/ bjects 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 moving wisf59e q7 2wovhth speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stoppio5hsev2q97fw ng?

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 pawr8bzam+ *y00tm5d rw nic, and skid a certain distance on a straight, level road. If you had been traveling twic8 *0rd5am 0wy bzwtmr+e 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 ellipt o5pf* ktu.r(/vwuhqnb( q3 :kical orbit. Neglecting any friction effects,ouqrh.k *pb(q(n:u/k5f 3 wtv 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 principle.6lta6dm/ hr 8w

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 negat(vu. d7i)npzzv.ba1b; s. n0cvt3jj0( tlscx ive 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 ground. jl-,g; ryf, tpzo vv1,A second object with four times the mass of the first if released from the same height. The potential energy o;rvtz1 ,,ypf g,v j-olf 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 spring causes it to stretch 5.0 cmmj6k;v4u- ir4.)we ,h:ieoeu2 g/pn oraj(ky. If another 0.200o- g44ho ee(wia nurij6er2; )m.u j,/kkypv:-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 energy of a syagr t 07)dup5qstem

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, to its potentir 4e4r:ptz+ hspbo*-ial energy +tp sz b4i -orrpe*:h4U.

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 hil( k;gcdnesy7 .l.

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 eqex1k:qn,3xn*m ya rl* ual speeds along a level frictionless surface. They both slide up the same frictionless hill. Which rises to a grexm*exq 1ay:r*,l3nnk ater 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 .i vdw,4yi):t6 nu fh*l9ybsh$m_{1}$ 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 fori 8ie 2sv6z 09mibcxl,ces. i zx0se2 iiv9cm6b8l,

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 top8+szl0 :a dyxi.o+(*cs fvtya of a building, through the air (air friction is present), to the ground below. How does the kinetic energy (K) just before striking.tdi+8 zaf: x( al*+0scvy syo the ground compare to the potential energy (U) at the top of 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 gains 30 J of kinetic energy. t.f7z dki* ,wtDo not ignore air resistance. How much gravitational potential energy did the bwz.tk ,*f7 ditall 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.ij wy qk:5sn8ajzy a78 (a+o7 nocb-c3 Do not ignore air resi+ yb-a73n 8y8aq5i cwsko:a 7znjc(jostance. 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 conservat/l()xkqnv( qm d,dnk1ion 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 is+janc*6s,rlls an1o5

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 SI uni 3.chd.mzfa 2sts?

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 1 z a -b.a1nke95khop:aiot1f4 mrrn; 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 one-third tao 9pcc4* g )bk4r*h pgnm*h94; hkmknhe time. To do so, your power output musm np k**n4co9m c 4)gp;hr9*hkhkb4agt 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, thr3s )hqczll /+e 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 obje 01tz 4mv92uqrsuw j,jr hf(n-ct weighs 90 N, how much work was m hns4 ,jr1j0-vf 9z2(uwtu rqdone 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 ou,+(8 zue +sydkd+, x;enix wqf 1.0 m, at a constant velocity of 0.50 m/s. Wx;kqd(unxy8+,de+ +wiz,esu hat 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 a constana. mz4sx*bf8gz 63jgl t force of 5500 N for a distance of 50.0 m. What is the work d gmjz x46lg8s3.bfz*a one 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 with a constant force of 5500 N for a d+vee )va,t j fm1lupt;kp6 )(sistance of 50.0 m. What is the work done by the weight of the el,; f tmekl+pvu jt)e61 av)(spevator?

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 . 60adhjwmy(quk 6 5nj-qh-8ymkplu8a constant force of 5500 N for a distance of 50.0 m. What is the net work done on ak.p qmwh0j hqnu658-u d6ly(y mk 8-jthe 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 a 6pr3uh fh(ha; $37^{\circ}$ 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, inclined at9 c69imr;7;jt oqundk z kjk1- $30^{\circ}$ 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 an icy surface (as zacdb ae e3 39z*;f)3mle;noisume no friction), with a force 93; zb dae3e 3lczefm)n;aoi*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 force. The graph in +mglj1bb) de-jw 17 it r:ih.-rncd, fqz+5z lFig. 6-1 shows the for7ibz b1 e:q1-+dm-i r. w5f ljz jr,dlhntc+g)ce versus 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 force. The graph i/sf6rto7 k8oio4 ixx 0n Fig. 6-1 shows the fost fxoi408i oxkr76/ orce 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 objeup;/mrd4tmnh, ,/ pgr ct in the direction of the force. The graph in Fig. 6-1 shows the fo/gtp dmurp4/ ;rhn ,,mrce versus the object's position. Find the work done when 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 0dvp j0luu) pkf)(+ fqdirection of the force. The graph in Fig. 6-1 shows the force versus the object's position. Find+p0kulffquv)0 )(p jd the work 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 to move a 55-:5mfbiw7s*,idw:qr5 pl-fxtkg cart (initially at rest) across a 10 m level surface. What is the final kineti,*tswlb7f-:wq5:rxd mi5f pic 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 (initial .9meo dyu33mely at rest) across a 10 m level surface. What is the final speed of the cam3. 9m u3eoedyrt?

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 e(4xzi6kur* d with a speed of 5.0 m/s. How much work is required to stop the mass?6x*ri4zud e(k

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 in7oh:lzadj2c .0s2 d ijus gu,*itially moving at 25 m/s, what distance is required to stop a car moving at 50 m/s underh*di7 usu z2g aloc2sj:d,. 0j the 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 bci 2guflf:1)annu, .ly exerting a force of 20 N over a distance of 5.0 cm. With what speed will the dart leave the gun,fn2 fgu an 1l):i.luc, 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 component of 80 N and 4g+9-iocw91,8i qxis d lofrs a vertical component of 60 N. The force is applied to a box wh9w,-xqgl+9f4d 8 ssioci i 1roich 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 of hay, strikinonw,bcp 3g :7 z1chi :ef(7, fwl8snl7hgv*vs g the hay with a velocity of 60 m/s. It penetrates a depth of 20 cm before stopping. What is the average stopping force acting ifgvz7bl3cssnf w1vp:we7 :8 nl(h*,gho c,7on 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 7.0x y*+1xjal;jg0 m above a floor to a height of 13.0 m above tj x *gxa;ylj1+he 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 ps zf1j4n t.zx9aiwh2 k d.(2eslane is 4.0 m long and rises 2.0 m. If the plane is friction2wi 4.snz e1ak9t(2xz hd j.fsless, 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 spri0qflt/vgr yrbpv8 +lni3 4o) ,ng to stretch 2.0 cm. What is the spriby q+ lrl/f)iv 3084rn go,vtpng 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 sp i) qvp9lrntt *.kwl 4y*,/lhpring constant of 60 N/m. How much potential enert/*lvrp q* . whi4pyl)nlt,k9 gy does 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 iw,e3cr bvn0 c9nitially uncompressed spring with a spring constant of ,c w0vr9ebcn325 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 toln 0h7j15x :;jkwgm*f rnnb( p stretch a spring of spring constant 40 N/m from x = 0.20 5;10(h mjgw*fnpnb7 kl :xrjn m to 0.25 m? (Assume the unstretched position 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 initially compressed gkzrbo7 . +*yy 3kp 5-nyrk1rrby 3.0 cm. How much work is required to compress the springny+rz g1o.yyb r7kk* krp53r- 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 from the top of a 50-m high slope. What is thergk 6ej3 c9h9np/r yk/ speed of the slier on reaching the bottomyc/e6rh3 gk/ p9kr9jn 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 hilsz w /x2tro ,tku,n++ml with an initial speed of 4.0 m/s. Neglecting friction, how fast will she be moving aft+mtk,/zx+2wt ru ,snoer 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 p ti 7kes4y;:lr;gpg2qlane. At the bottom, it has a speed of 9.7;kq:g etp rgil4s2;y 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 it is 0.70 m above the f6v cucxxyiq;y + v-1u8loor, its potential energy exactly equals its kinetic energy. How fast is it movin-ci; c 6 vyv8xuyxu1q+g?

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, weighi xgu+tmnwp 6-*lq7zxol k96-rdups*0ng 10 N, blasts straight up from ground level with a kinetic energy of 40 J. At the exact top of its trajectory, its total mechanical energy is 140zx6go*p lmu sdkn-q 6r+x 7put*l9- 0w 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 kinetic energy of 220 J. Atdzb5p i 5nbdtkrxu* gbc,; 944p*nt7- s .aems the highest point in its trajectory, its kinetic energy is 120 J. To what vertical height, relative to its launatp-r5 n*,. zm4eg six b;5u9sd*tdb nkcp74 bch 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 abov eraqjxz8-0*)-/ny* n xx src+ fimwm-e 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 nexx )xq xn/wz-c* j-fni08ra+ e*rmyms-t 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 point 45 m ab38yu-x2a lkrt ove 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 next3ykx l-u t2ar8 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 dip xp 5, dvwas.+(omwz2h,+h qhrwith a speed of 25 m/s (See Fig. 6hmh ,q ax p+vs+wr2,wozh5d( .-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?

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 i( v* (lbuv:h62kh og ;xvn8cddam; :kits 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 pendulum of length 50 cm is pulled 30 cm away from the ver)f0xgf3vp f;dv4r yl .tical axis and released from rest. What will be its speed at the bottom of its sw0f.;)r 4vgyx lpf vd3fing?

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 at 25 m/s hits an initially uncompressed horizontal spring7*f80goj u m( bw4rluq with 4fu( g*7omwr8ul j bq0spring constant 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 2000 kg car to stop- kyu nj 0lt6e)s)9ikl for a red light. What work is done j ku06kl ei)l)s9 nyt-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 1pvv ;w0fhx8w z17il p ,dkz 6y,ekc)sa horizontal surface is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slide befor0s1zz 6f;8 kvdh v,w,piec7lp1w xyk)e 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 has 24 J of kin6fesq*mg;(z s4,u yz metic energy. T s zq ,u4zsm;m6f*g(yehe friction 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 surfa,ymu9 ,n;5 egw9xpb bqce. The coefficient 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 k bxgw;,e,5 m9u qb9pnyinetic 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 .)54otqsmjvdhk+8r 6a fol 1tjf-l/y rest from the top of a 50-m high slope. If the work done by froh 85fm+46ys1)q-jlvt afrt /jk.ldoiction 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 lb2k)jh:jhz 1o xj +kv9ygc2,up an inclined plane. The plane is 4.0 m long and rises 2.0 m. It requires 3200 J of work to get thy 9hjv2c 1:l)jk+hz 2gob,xj ke box to 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 from rest ne ) (loq3cm:h cvn6t)l/nfr.at the top of a plane inclined at 20e above horizontal. The coefficient of kinetic friction between the mass and the plane is 0.20. What wil/6leq(vmnn o 3fl)t c. cr:nh)l 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 strik7kd 2vb+i/(xcjapgh+m ; h2 nles the ground with a velocity of x +72ij/(dc2lg+apvb ; n mhkh7.00 m/s. What average force of 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 energy when he runs up a flight of sth+-sq x:jpzzta 1zo :2wc bz33airs 10.0-m z:zp: 3x cz z1q+3was-jh2obthigh, 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 an object with a constant velocity of 38 u w:mogzb86dtm-wc 5.0 m/s. What power mus-:gtwo z3wb886mmduc t 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 -2uuhnfffs)x /97ez2u yf3c bt idd,)by a 1.0 hp motor that runs for 1.0 hr? (1 hp = fzbtuc s yuu) fn)3,dfh 92if/x27ed-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 while riding. How much force does her376fr/vv k 2tkddf mk/ foot push with when she is travevk3d f r/fk/2t76m kdvling at 8.0 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 from 0 to 25 m/s in 7.0 v,4vj tb71m 4 -/kdkat eat(pzs. What is the average power deliveret -atmtdv/(4p,kz4 ej k 17bavd by the engine? (1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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