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

1#

What is the correct unit of w,6j 7js2i o:uj.8zi;wrrscf s ork 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 therd-gz h )zk0 mom,wc./re 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 of wr-.p.nr.lrjt6jelhjk+ dy -)ork yon .--) lhj.r.+jrkjdy6 l terpu 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 txu/e mac0l44 1sgo 1lhhere. How much work is being done in holding tlcsu40h1m/l1 4o ag exhe 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 constant))xeooj ntin--i6 f.y velocity carrying a 10-N object, the amount of work you dnx6-o j)oieniy -t.)f o 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 returned t4 -psla(g eca8o its original posic4les pa ga-8(tion. If the total 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 centripetalo)/65 bwz ,bb/h6pd4hqhrw yw force acting 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 vezrn(f ) 6y 3);mxtvoup. Compare 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 dym); r)f3vxzt6v(eo nown.

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) wd7jkihk*wr( t,m .t3saaa. a137 /jp u-qirograph, representsmo q*hirr,ww a. aak1ktj773i.a(/p 3du-sj t

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 positio+7lq hskf,hreb 8e h35n (F vs. x), what represents the work done by the forh sf7ehbhl3 qk, 85e+rce 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 opd7 l1*y,nf yhbject is positive, 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 ist;,erj)u: 2 bsoze x;s 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 the object's kinetic ene xu3lh:q.kd275 hgwtm rgy

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 twdigzln(1a i0) ice the speed of the car. Which statement is true about the truck's kinetic energy compared to that ofnlzi1ai)0 gd( 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 thy 5-acj+ dq a39zx ibtt t)a,:wbx*hr(e mass of car K. The kinetidj-35ybtta )r,i(qzx9:haa*xctw+ b c energy 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 wall and bounces b9vzz6 n tmugy)mt u+g6()zr j,ack with half of its original speed. What is the ratio of the final kinetic energy to tmyz(6t) 6u)gm grz uv9zj+nt,he 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+puob4d 5t8oc3ovqz* cq .dd: and a pebble is moving at a speed of 5 m/s. If both objects have the same kinetic energy, what is thddzuo bt45c 3.q8+vo: cqpod*e 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;w jhjf2wb0/d -kg mass is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greath jj2wf;dw0b/er 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,a85o5h0 th pagcu v92s and skid a certain distance on a straight, level road. If you had9o5 hah0ac t8pgs2 v5u 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 zy3 ti2039gxhsmtxr: pbi.9r u9lm;o the Sun in an elliptical orbit. Neglecting any friction effects, what happens ;gixmpul b t39:h9m.o3 xr 2z0st9iryto 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 principl-5 nbbjy:4ooee.

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 negatioq.xm:: ffhufifaes32e 14d-4k z gs- ve 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 grounda- 7ccr8-,rfasgi7 p.guwk s;we6 cu5. A second object with four times the mass of the first if released from the same height. The potential energy of the second objspwak ;68c g-7ur7 swucig,cr5f - e.aect 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 e;0 nw -1 v6ook/jcvi8qlit.ab nd of a spring causes it to stretch 5.0 cm. If another 0.200n.i voc;w6j i 8o0-valkq/t1b-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 n(*ph9b p2g eysystem

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 kinetit,w62os/epu ravd5 : tc energy K, to its potential energy U5udt6at2p /:swor ,ev.

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 d -8tydy4pux+lffg0; p6s:hw friving 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 object arq/a-r;rdioq vr6k+ l g)f7)g ye sliding with equal speeds along a level frictionless surface. They both slide up the same friction ri ol-q ;vd7) g)rf/rk+a6ygqless 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 mh25zl 41g bh2kh:vus$m_{1}$ 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 enerk 6a gmzstj msiiykj;0g3 xd9).no7 9+gy for conservative forces0.6kj9 xko)7niz g mtd a;+ms93jy igs.

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, through the c rjaj :8j.okwra zno;+o7-d7 air (air friction is present), tod.-wro anjora7c78kj+ : ojz; 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 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 kinpg ( 5)* i:rqivgqt8kpetic energy. Do not ignore air resistance. How much gravitatiorq)p 8ki5v gipq(:tg* nal 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 gravitational potential enerbl 1qmcg - m5a*0 gs4l6bonkavz:.f7q gy. Do not ignore air resistance.qqna6 blv so7-m ab4cm*f 10kgg5:zl. 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 rg al 8 k 5,.as)lkeiff/jfb6(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 ishbs c;bq 5xsbgsf-- /5

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 p,l kymxt8o xf02o:c;0e*ishgower 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 is8 -njfcei++t g not a unit 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, ;lbl49 g1n4qp;lysbdyou did 3 times the work in one-third the time. To do so, your pb s;llq14b pdny4;9 glower 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 a cont6(;(lzhvt y o,nc8 rogntz.1stant 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 object weighs 90 u):o kigje39y13yp12wfbp kb qcamojm)v9 ,/N, how much work was done in liftk/jv39w3ki)y21co) bga1y9,:qfm mpbpuo e jing 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 1.0bqlh t3.q5i mb)y;: echk b77k m, at a constant velocity of 0.50 m/s. What is the work done by the w h.yb 5qmbc:; kkbqt) 3ielh77eight 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 constant force of 5500 N for a dista-ke (if:n ;bipnce of 50.0 m. What is the work done by the 5500 N force iefip n(-bk:;?

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 5y(u pel5aby04 500 N for a distance of 50.0 m. What is the work done by the weight5eu (lyypa b40 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 5500 N for aey 5 :qsh4/01w nrsvaq distance of 50.0 m. What0:1qwehs5say 4/ rqnv is the net 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 along10* j cj2fy 4luhtp:tn 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 8.0 m down z7v fwd v3p-aeow b3 ;o)k+b,ra 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 an ics6(2+jn4 c yqs f4ym kfwk r;*qlwfv80y surface (assume no friction), q6*syf4qj +2c kl; nk0w4vwf(f8ym rswith 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 force. The graph in Fig. 5iwakcz u )3.upg66ur6-1 shows the force versus the object's positi)k3 6w6uz irp uugac.5on. 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 2fq va -uvh0tcz:5 od )g9nb5fjji7g 5of the force. The graph in Fig. 6-1 shows the force versus the object's position. Fizvj75i:f)udb nh5ggf50t2 qcao-v j9 nd 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. Tyrtbu ( ;s h4nygum5):(vp7ay he graph in Fig. 6-1 shows the force versus thens;(hy4(5 byut:mpr7g vy ua) 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 direction of the force. The graph in Fig. 6-10ph0xaw *)lgt blc00o;svo*m shows the for colbv0ogp0)t slh0*;*0 mxwace versus the object's position. Find 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 iskhw2.8j nbmru0lntt 3qd 4:l *t w7*nw applied to move a 55-kg cart (initially at rest) across a 10 m level surface. What is the final kinetic energy of the carww.nj h nbu*ld:t*r802mq3tkw7n4tlt?

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- y6 0*dibgfs)lgnuu 1:kg cart (initially at rest) acr6d)giulf ubn*g0s 1y:oss 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 9y;cq1u,)49owhx z xmh ;tdjyqg :7xc 5.0 m/s. How much work is required to stop the mas7;mw4hy) od x cuq9c,;qxj hzgx1: 9tys?

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 moving at 25 m/s, what distance iwhsszx9 0(2y saqv:u3s required to stop a car moving at 5ss30y9wh:ax(zu v2 qs0 m/s under 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 gh*y av2 ,po9.,hul l 8ogijq;hun propels a 10-g dart. It is cocked by exerting a force of 20 N over a dista;alo.oh 9hj2gly ,,h* ivq8up nce 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 component of 80 N and a vertical compe ducuth3n) iryo1dl1 /0) i p+r90nfionent of 60 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2.0 m horizi03n edi ho) d+1uu 19tiy0frc/lnpr)ontally 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 isfhk(,egk,igaz)e .6; zq8j bg 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 stopping. What bfkkz i ,.a) hzeg,e(g6q8; gjis 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 mr0 wrz 48l/hhcre0 j0 lpzl16x above a floor to a height of 13.0 m above the floor. What is the 6 p4xhrr 0l/z81jl0 ewl0rhzcchange 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 4.0 m long and ricd:q/ rk-mnyq m509uc,gj qa6ses 2.0 m. If the plane is frictionlecr5 j dqcny9kq-g /:m,6umqa0ss, 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 2.0t*;t 7b-;vrprc6vkmn6x0i rim /tnf* cm. What is the spt0 xvk itf7*nnc r-mbi;6r6t;/ m*rpv ring 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 spril7pqpk06fwr(i r(9/tdbj-9tk c3 bq-vwk cj;ng constant of 60 N/m. How much potential energy (0i-9kq9pq-t r /cp 7cfdkj(w6vl bt3b;r jwkdoes 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 require23j() uk4ey b04y saqmxd2somd to compress an initially uncompressed spring with a spring constant of 25 N/my(m4 s3se2 x40u2byo)jdakqm 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 nutyee7ss.qt8g 89t 4r3rt ; ato stretch a spring of spring constant 40 N/m from x = 0.20 m to 0.25 m? (Assume th;q7y t et. 4 nguss9err88att3e 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 con m-4/z 8/yrf7vffq lvvstant of 15 N/m is initially compressed by 3.0 cm. How much work is required to fffv7mylvrv/4q8 / z-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 from the top of a 50-m dp pgn7+cwigt:h2 d5+high slope. What is the speed of the ski+p5w27dp+i: hd gn ctger on reaching the bottom of the slope? (neglect friction)

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, pus3(mmn3p,6x kqi wwtm4uvi /b ,hes off the top of a hill with an initial speed of 4.0 m/s. Neglecting friction, how fast will she be moving after dropping 10 m i3(6m umx/b qpwi wi,n4,kmtv 3n 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 plane. At the bottosd.t3 :.tdbpx urep 8* td(7lom, it has a speed of 9.80 m/s. What is the vertical heighdd.b.rl7 3p:xe(otu t*ts 8d pt 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 i jr9x*drt yjzquuuss 8+(37bsqe0(0 ws 0.70 m above the floor, its potential energy exactly equals its kinetic energy +qs3eusrq0d8(7j9ys*uxrt z(b 0 jwu. 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 -y+ md5ix5pe t10 N, blasts straight up from ground level with a kinetic energy of ex- d55 imt+yp40 J. At the exact top of its trajectory, 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 9 2( uiiwkrxu j6vo +)-4ibydkwith a kinetic energy of 220 J. At the highest point in its trajectory, its kinetic energy is 120 J. To what vertickx 2+4dviw(u ib)6 yur k9oj-ial 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 40pyg(5gap fo from rest 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 0g ag4p(oyf5p 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/sx -s5nrl. d ((5lsqsnn at a point 45 m above the bottom of a dip (See Fig. 6-.(5rsqnls n l(-snx d52). 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 i d9p17mls;psbottom of a dip with a speed of 25 m/s (See Fig. 6-2). Neglect friction, what will be th 7idml1sp9sp; e 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 swinrz2rjorz364/4:ykp k h e l5vbg (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 0.13 m aqvzn .46ybg1 f wvcl+k*264nas a7tb dway from the vertical axis and released from rest. What will bldw 46nva*6av.s ng41z7kqyc 2bt+ bfe its speed at the bottom of its swing?

A. 0.1742 m/s

B. 0.464 m/s

C. 0.697 m/s

D. 0.581 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 anc5 qf7 )*khxfw6yk/keae22nes; z4 t h initially uncompressed horizontal spring with spring consh a/e*2z;x6 wkqkn e5f)thk7fseyc 42tant 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 caren 1nk,mm7nbr 7p5 l*d to stop for a red light. What work is done by the friction force agm nndlk,7be1*n7r pm5 ainst 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 surfac f ;w mru9pj5y h judj1:pib5rx04x4w0e is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slide before comj5 jjyd0w4 r : ui1905ppbhxxuwr4mf;ing 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 kinetzc88n h wt +xzq84zj ,scx0uq+ic energy. The friction force on it is a constant 0qwxz jc8q +xz8h 0 z4ucnt8,s+.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+. -5x6ros9svc*loctk0 al zb on a level surface. 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+xr o.l -5ot*sszvkl 6bac 9c0 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 4svoc5zg 32z aj3c-y );edxux from rest from the top of a 50-m high slope. If the work done by fri2xuadgo-j;s4xevy5c)3c zz3 ction 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 plan) xopw703 t 6ksaoa(zqe. The plane is 4.0 m long and rises 2.0 m. It requires 3200 J of work to get the box to the topas673 kz0 oqowp(axt ) 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 at the top of a plane incr ;)cr1l:k vi*v e;;ehc;h mmvlined at 20e above horizontal. The coefficient of kinetic frictkh;1rcv;c rmm);v;v * el:heiion 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 stlzrc5i bit65k g33t3qrikes the ground with a velocity of 7.00 m/s. What average force of air frictioqk33i tl t5bgi5z3rc6n 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 6+l4jyqa aazje45pm99 pd;mq runs up a flight of stairs 10 dq5 majjzma;e9pl9+yqp 6a 44.0-m high, 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 constan qw az .1ux w)i++rm392skqydat velocity of 5.0 m/s. What powera3w 1qyqwu 9m r)ik.2ads++x z 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 -/ g njqsf lopu5 +l.g5 w j3k(lrz8y4bz/ds3xa 1.0 hp motor that runs for 1.0 hr? (1 hp = 746 3wzsx o8nfslg kruj5qyl +b4.3 -ljg/5p/zd(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 503)4wi mrz*jbqatf/yw2ae h710 W while riding. How much force does her fo32zj1hib)wm wya*/ae q 4r 7tfot push with when she is traveling 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 s. What is the average powern:5d9i+x*do*m mb*p6jvnsv c delivered by the engine? (idnd+c* xv*bm:* jomp n659vs1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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