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

1#

What is the correct unit of woro c;f4p6ft3zi k 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 there is no motio)(*9v ptey/ts7tsg. kj + chbpn?

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, t: 8p3qe):,gy6x+yifcrwml hn at9tf4he amount of work you rfmw) hl+:e,: xp y4yc89g6niaf3qttdo

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. ebp/95 u)er,5smzzgbv ,dsk*How much work is being done in holdinz,z gebk*/ dr vse )595upbms,g 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 constant velocity carrying a 10-ik*;/zna v li2N object, the amount o;vinl2*zk ia/f 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 iyl(.*l9f vee lifted vertically 3.0 m then returned to its original position. If the total weight is 30 N, how lif 9l(.yeev* 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 a w(kzwc fs2b7d/sm;0 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 up. Compare the sign of the work done by grxqcwt/9i)3)he xrqyd ;laa+)avity while the ball goes up with the signa x er ch;qi9d /tyqaxw)l))+3 of the 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, ot v 54iv+af(wpijdfqwk) -83 fn a Force versus position (F vs. x) graph, represents5f8v(fpjd3 wq) k ft4viw+ia-

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 vs5db ai5l6yjxm h2iap kll e6b)ya g/0/p97d+y. x), what represents the work done by the force +b9la/0 lk5i2mx6epb y7yjdaldh 6pg5i ya/) 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,r0+*l gz.feq a then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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13#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is negative, then the object's kinetic ener .l-kw1bof ofu;s h73cejm7o7gy

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 t)zy pn (e9ob4hhe 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 tvh,1; ns /cspjz:jobx.4du v1he speed of the car. Which statement is true about the truck'j cdss4vb ojux v11;,/:.p hzns 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)b8jj:ti k*mt car K, and car J has half the mass of car K. The kinetic energy of car J, compared to car K is:b *t m)ktjij8

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 s7 gc+cwyte7 5dvb+9l. What is the ratio of the final kinetic energy to the initial kinetic energyy7ev97+cgd+5 tl bwcs ?

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 b/pjhbpb s).+pebble is moving at a speed of 5 m/s. If both objects have the same kinetic energpbhbps.+j/b )y, 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 sr/bchf 36vn6v;vzhes1e- 3gyzr q(:z peed 2.0 m/s. A 1.0-kg mass is moving with speed 4.0 m/s. Both objects encounvneh6 hs b1-z(3 rv g cy/6f:rz;zveq3ter the 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:0u f** mgiuf qz ofjl 81-*1:uyrkagd skid a certain distance on a straight, level road. If you had been traveling twice as fast, what disiod*8yz*gfuqfmr0 *1-:au jg :l 1ukftance would the car have skidded, under the same conditions?

A. It would have skidded 4 times farther.

B. It would have skidded twice as far.

C. It would have skidded 1.4 times farther.

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

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A planet of constant mass orbits the Sun in an elliptical or cmn :-*-jdzh)qo+ctyh ,rg7 ybit. Neglecting any friction e cqgrn-yyjzo +*d)hmt7c:- ,hffects, 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 principlp b - tekkig3o+pob*s tg6w777e.

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 h-oknot5lob4j 6f9bfx8 ob vy,q .6.wfave 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 s7mr wq;w**cl from rest a height h above the ground. A second object with fourmq; * clw*ws7r times the mass of the first if released 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 atta y*ded s-d-l+;w+hn6m50vblik ir+ba ched to the end of a spring causes it to stretch 5.0 cm. If another 0.2nha -*5d-bv 0m riy+db6d els+wki ;+l00-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 s5nxf u5s)ozufa;x n * v8x*cb3ystem

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 tr(;ojb.yv,en dee. Compare its kinetic energy K, to its potential enern jy,b;e.(dov gy 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 o8.u(z/fynffg k; ask9z2k;uu f a car driving up a hill.

A. entirely kinetic

B. entirely potential

C. both kinetic and potential

D. gravitational

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31#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A lightweight object and a very heavy object are sliding with equal speedspnp8hlwie y6. 5r70 am3gtkf g nh8e3/ along a level fric7f.gwp3p 0 e an6l88egh3trh in/kym5tionless surface. They both slide up the same frictionless hill. Which rises to a greater height?

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

B. The lightweight object, because it weighs less.

C. They both slide to the same height.

D. cannot be determined from the information given

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32#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Consider two masses 2bjek84,nxtx5tda s) $m_{1}$ 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 f3pkli62u q zp:*23fyzu s n(gfor conservative forces(z2f632pqs ulky3fg n u:* ipz.

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 aiu7 wfi- fr8csjt1s6o n;bh7 k1r (air friction is present), to the ground below. How does the kinetic energy (K) just before strikinsfw cs1r nko7tb fu j7hi1;6-8g 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. Do not ignore ly3h tadj4w50 air resistance. How much gravitatioj wyld4h 50a3tnal 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 la,wf (bda8f,e;ri/w potential energy. Do not ignore air resistance. How much kineti, (fl daer8a;f/,w bwic energy did the ball gain?

A. more than 30 J

B. exactly 30 J

C. less than 30 J

D. cannot be determined from the information given

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37#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the law of conservation of 0;ce2udtjuwpby38s y2ukc*y;uj z93 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 isj)cx ; om9:zsg

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 unitrfb(f0x *n*v v of power 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 unit ofkrse vu/u lh,7 wgn09- 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 o0(v )rclkge,h ne-third the time. To do so, your power output musv0g r,ek()c hlt have been

A. the same as yesterday's power output.

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

C. 3 times yesterday's power output.

D. 9 times yesterday's power output.

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42#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

To accelerate your car at a constant acceleration, the ia0*3p nrwg 9kc7wn.4bf, ofy 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 907maw ;iu1 orl x8g(fq7 N, how m xg7lw7(fmi ora;18u quch 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 a)s(d p -buof5book up in the air a distance of 1.0 m, at a constant velocity of 0.50 m/s. What is the work done by the weight opbsa -od(u)f 5f 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 ofbme6.a/ z ees0 5500 N for a distance of 50.0 m. What is theee/mzba60e s. 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 with a constant force of 550(jgkra-2r jo r 3h6,rn0 N for a distance of 50.0 m. What is the work done by the weight ofjj-or 2ng3 h ,(rrkr6a 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 a dirx kgt -d nvq7;8j7, cjt.0 2dxmhgog2stance of 50.0 m. What is th7r.-tdh nj gx;x j m270c2d8qgt,kov ge 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 az* hnk7f wdmlr8q(iln/( p+. ylong 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 a ramp, inclined at p.,:ibyo 1pah $30^{\circ}$ 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 iuj9os2ju l 9gyw;3+g6 *y grbyn a sled on an icy surface (assume no friction), with a forlwby 2*jysj 93g+o guruy6;g 9ce 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 (+ 0vxsg2h)l 0qk fyenvb1mc0in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves from 0 t 0+vf)cqxv lkhe 1g( 2sbymn00o 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 dim3 3pwj3pkn h*cv,j8 rqsr5 zti:(z3y rection of the force. The graph in Fig. 6-1 showspk3 jhz8,c i:syrrwj qz3tv5*mp( 33n 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 thhbq d 1*hw,a8mwpjqm 84:r-kwe force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object movmh4 dw*b p8qk:81wahmjqwr ,-es 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 grap56+dcg jul6ych in Fig. 6-1 shows the force versus the object's position. Find the work done whel5cjcy 6ud6+ gn 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 applj3m i9ov4lxk 0b*ju7gied to move a 55-kg cart (initially at rest) across a 10 mmj ijgu0*ok v9347blx level surface. What is the final kinetic energy of the cart?

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

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

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

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

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56#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A horizontal force of 200 N is an3e, sc6+i6wosk7 7ukl n +o3jtwc wj-pplied to move a 55-kg cart (initially at rest) across a 10 m level surfsc7iwk7jo,n3 +c-+3l nwwt je6 sk 6uoace. 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/seqr8o0;edj3 qc.9 e80 qhlr yn. How much work is required to stop the yhoc0;qe90r ed.e qq38rn8j l 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 moving at 25 m/s, what distance is r/y ww j(4-rquvq:kj4id5q-8anpj6ms92 u ctaequired to stop av prsku9w2i 6 n(aa 448j-c- uy/dqjqt qwjm:5 car moving at 50 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 gun prou;w:8glvrqivisp2965 nc-2 xtox q3lpels a 10-g dart. It is cocked by exerting a force of 20 N over a distance of 5.0 cm. With what speed will the dart leanc3;i vl82s txog26 uvq5rp qw-xi l9:ve 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, cjtkm 4lgucu/l s-3) of 80 N and a vertical component of 60 N. The force is applied to a box which rests on a lej-k 4u) 3c, /cglmtulsvel 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 horizonta;nu l4oqd5 t na/r*/qllly into a bale of hay, striking the hay with a tnd5l 4 ru/oql*/n;aqvelocity of 60 m/s. It penetrates a depth of 20 cm before stopping. What is the average stopping force acting on the arrow?

A. $45 \; N$

B. $90 \; N$

C. $180 \; N$

D. $360 \; N$

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62#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 15.0-kg object is mo7 2 ycyl3vj-(7gix hsxved from a height of 7.00 m above a floor to a height of 13.0 m above the floor. What is the change in gravitational potential energyiy73j s7xx( hyv-c2g l?

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 m9vjx 9wgti318l3i iit::fnqinclined plane. The plane is 4.0 m long and rises 2.0 m. If the planeii wt39qix gt81l:9vmn: ij3f 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 strhsl6 6 kddp2r+y-5ik cetch 2.0 cm. What is the spsy kh2+6 idkl5-p6rcd 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 spring constant of 60 N/m. How z: kf94 bcxea-much potential energy does it store,9ex4 a-bzk: fc 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 uncompressed f p .mn7/ /g.moylgn(rspring with a spring constant of 25 N/m by nmo.fgyg m7/rpnl(/. 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 strete+ f+6gtsvs5 m5sfsy*ca1dvoc . w9h ;ch a spring of spring constant 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretched s+9*wvo f6tve ;m 5cas d yh1cs5.f+sgposition 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 initj qo-619jin 5muvq- joially compressed by 3.0 cm. How much work is required vq6 i9u1j-5oj-nq omj 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 from the top of a 50-m high slour6,o+sbiq h8 pe. What is the speed of the skier on reaching the bottom of the slope? +i8so6,hu qbr(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, pcr;f54 fz irq-ushes off the top of a hill with an initial speed of 4.0 m/s. Neglecting friction, how fast will she be moving after droppin54q;fi z-crfrg 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 plane. qoqv4s8) 5too At the bottom, it has a speed of 9.80 m/s. 4 8vots o)o5qqWhat 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 aboveo 1n vwci6 5yut5nby0: the floor, its potential energy exactly equals its kinetic energy. How fast is it moviny:n5bt0ciyw6o u 51n vg?

A. 3.7 m/s

B. 6.9 m/s

C. 14 m/s

D. 45 m/s

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73#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A toy rocket, weighing 10 N, blasts straight up 12 zvs0fv 9cldfrom ground level with a kinetic energy of 40 J. At the exact top of its trajectory, its total me2sc9dv 1fv 0lzchanical 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 kinetic energy kdw9cs.lbbp*e/xk u dx-)*: cof 220 J. At the highest point in its trajectory, its kinetic energx 9*w.dd- c *c:ekbusplbk x/)y is 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 te iqcg, /t*y3rhe bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at tryq,3* /geci 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. 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 ofhza031sldf6 , .3+hc tw tjpdk 5.0 m/s at a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed o.3 f, ap twh0tkjcd6ls1+3zh df 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 tvssvixd;jc 0(+ 9pw 2ihe bottom of a dip with a speed of 25 m/s (See Fig. 6-2). 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 of0i sv+dx;v2i9( cspjw 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 df6pb/+n*+ wj n6zkpjspeed of the ball at the bottom of its swing (point

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79#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A:2.2 m/s

A. 3.1 m/s

B. 4.4 m/s

C. 4.9 m/s

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80#

( 1.0 分) 切至整卷模式搜藏此题

难度:2

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81#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2-kg pendulum of length 50 cm is pulled 0.11 m away from the vertical axis ,-6o(rzmk uw, bz9ri,kq1gwf and released from rest. What will be its speed,k,fb9owr iq1 m6kz,wz (u-rg at the bottom of its swing?

A. 0.147 m/s

B. 0.392 m/s

C. 0.588 m/s

D. 0.49 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 i b*g rz99-3.tck 3*wjoxcl fnsnitially uncompressed horizontal spring with spring ckts9**3cbfl-.g zr 9n3 ocxjwonstant 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 mly0y3g4m oewo )u61a22 m/s, slows down her 2000 kg car to stop for a red light. What work is done by the frictiooo 3lmau1)4 g6e yw0ymn 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 forhld3/ j4dxpk )ce between a 60.0-kg object and a horizontal surface is hpj )d d/3xlk450.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slide before coming to a stop?

A. $15.0 \; m$

B. $30.0 \; m$

C. $375 \; m$

D. $750 \; m$

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85#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 12-kg object is moving on a rough, level surface. It has 24 J of kinetic ene iai9 n xs a2n+j8hhl;wm,4fu:rgy. The friction force on ai: a2u,h 8f+xn4; l9mihsnjwit 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 e6tks)gozy7;: sb ssi33 7a0s *kcd tl8l4big2.0-kg mass 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 is the change;7sie:o 0bg74tc yskgk63 *l a slbstz s3d8i) in its kinetic energy?

A. $20 \; J$

B. $39 \; J$

C. $46 \; J$

D. $61 \; J$

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87#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 60-kg skier starts from rest from the top of a 50-m high slope x6,ww4qwhmmpa v8b 7-. If the work donqph8b avww7,wxmm 6-4e by friction is $-6.0 \times 10^{3} \; J$, what is the speed of the skier on reaching the bottom of the slope?

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88#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An 800-N box is pushed up an inclyay/bv(fgqs4;s x3 t/ ucu-j0ined plane. The plane is 4.0 m long and rises 2.0 m. It requires 3200 J of work to get the box to the top of the plane. What was the magnitude of the average friction force on tqg u(sau/yb y4c/fjs0t;xv 3-he 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 to l cw66j0fk1ecqf*mm( p of a plane inclined at 20e above horizontal. The coefficient of kinetic friction between the mass and the plane is 0.20. What will be the speeq 0l*cj1m6fwe 6f ck(md 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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教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

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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 with a ozb1ys/56 fbiw21bjl velocity of 7.00 m/s. What average force of air friction acts on it as itl52y/ f1z ibjw bo1b6s 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 np6jma-y0il: .cnqqio*,d r- he runs up a flight of stairs 10.0-m ji6 nr-,a 0. olqq mpicny*-d: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 conkr. ,/b3fxtnjs/bs 0fstant velocity of 5.0 m/s. What power must be delivered to thetnx jb,s0 /sbkr/. ff3 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 4r 7t ,n7bbbmcare used by a 1.0 hp motor that runs for 1.0 hr? (1 hprb 4n77,bcmtb = 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 doeswbku w8 vk18d/ her foot push /bkuvw8dw 81 kwith 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 frocx (1dqtomeru8+i ta5 95d3q ol/cy s*kdgq(3m 0 to 25 m/s in 7.0 s. What is the average power delivered 3 sc*tqqtm1io85r x(3q(l/ ddduagc5yoe+9kby the engine? (1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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