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

1#

What is the correct unit of work expressed in SI unitnhvx *t f4m:eacr)64fs?

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 agkvb-ad.y.k5u8fz2ogacf.uuj8./e 4lr 6 sj system if there is no motion?

A. Yes, if an outside force is provided.

B. Yes, since motion is only relative.

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

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

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3#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you push twice as hard against a stationary brick wall, the amount ofr x,i7qp9fj t9 work yo79f it,r9pxj qu 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(psr5 )wg*kw *opu ,lt 2.0 m vertically and is being held there. How much work is being done in holding the box in*5g pluw)okst*pr( ,w 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 nywlcavs47+ypa* e/ 4 rg-; yg7t1xgrcarrying a 10-N object wga;4pgr e71 nxyr+ g-alsyc *t/74vy, the amount of work you do is

A. more than 50 J.

B. equal to 50 J.

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

D. zero.

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6#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A container of water is lifted vertically :5 4owomjjjaxi7 6af-3.0 m then returned to its original position. If the total weight is 30 N, how much work w 4 -oim6j:wf a5xoj7jaas done?

A. $45 \; J$

B. $90 \; J$

C. $180 \; J$

D. No work was done.

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7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Does the centripetal force acting on an object do work on the objecvl 1 /h-zlhipxa2z jqg(m9m0- t?

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 s vcl 8jn:84i3z j(a2bybcjy- kign of the work done by gravity while the ball goes up with the sign of tha4jc j8 yckv2 zjy(:nbl83- ibe 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. x) graph, repreq1cw3+f oy3 y4s:b 3ealx9eyx sents3xso x9+4 e13eywcbq y:l3yf a

A. work.

B. kinetic energy.

C. power.

D. potential energy.

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10#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

On a plot of Force versus position (F vs. x), what represents the work done3 uv,(kqg;s wy by the fy(vskg, 3u;qworce F?

A. the slope of the curve

B. the length of the curve

C. the area under the curve

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

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11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity $\frac{1}{2} \; mv^2$ is

A. the kinetic energy of the object.

B. the potential energy of the object.

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

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

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12#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is positive, then the object's kinet,;/9y8did;qh jdg6x0 fx dptxic 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'v4 +e(e 4gsytps 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 t:7ifn /scf 2qw9citarf): )hnhe object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A truck weighs twice as much as a car, and is moving at twice the speed of the *u pqj7v 3gbplejj,/; car. Which statement is true about the truck's kinetic energy compared to that ofgv/l,upjjj* 3e b;q7p the car?

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

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

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

D. The truck has 8 times the kinetic energy of the car.

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16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Car J moves twice as fast as car K, and car J has half the mass of car Kbzom.p8 t:xy 3u. hii5. The kinetic energy of car J, hxib5 :.p z .im8yto3ucompared 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 origlfhos)tw1i ,9bzm-zo(+ j zp i:sw8m3inal speed. What is the ratio :+tz)sz( 83jwmi izfpowm ho ,s19-bl of the final kinetic energy to the initial kinetic energy?

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

B. 1/4

C. 2

D. 4

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18#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A brick is moving at a speed of 3 m/s and a pebble is mov2hlnj *5(hkec:ib lr+ing at a speed of 5 m/s. If both objects hak 5+:jen*hc2 lil b(hrve 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 v*5ao0qf/ q*yzss*u nmass 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 greater distance bz 5 q*ou*ns/sfaq*y0vefore 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 skisl hg4nqxb,vn,) 5 hn0d a certain distance on a straight, level road. If4g,5q lh)nb0vhxsnn, you had been traveling twice as fast, what distance would the car have skidded, under the same conditions?

A. It would have skidded 4 times farther.

B. It would have skidded twice as far.

C. It would have skidded 1.4 times farther.

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

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A planet of constantc b2.uz-p6 b*p v)ufb-q: ztyu mass orbits the Sun in an elliptical orbit. Neglecting any friction effects, what happens to the planet'cppf6- :z2ub*.-tb u bzu vqy)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 e3bjki s0b+ntf5m5 f6e.

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 sy yfgx*gxzy7v(gj062jx x1-k fstem to have negative potential energy?

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

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

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

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

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26#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object is released from rest m z9zcyg( .u9sa height h above the ground. A second object with four times the mass of them9u9czg(z y.s 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 attached to the end of a spring 6 wl z-1.gg iox0bftf:causes it to stretch 5.0 cm. If another 0.200-kg mass is gz:io-ft1f .lb0w6 xgadded 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 ene y0z,z 2ahw0rrrgy of a system

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

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

C. can never be negative.

D. is constant, only if conservative forces act.

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29#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An acorn falls from a tree. Compare its kinetic energy mo*c5b vyyu91* lg8 xqK, to its potential energ g8 yvomquc91*by5lx*y U.

A. K increases and U decreases.

B. K decreases and U decreases.

C. K increases and U increases.

D. K decreases and U increases.

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30#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Describe the energy of a car driving up a hill.(cm jyu5c14vz81m stcqz64s o

A. entirely kinetic

B. entirely potential

C. both kinetic and potential

D. gravitational

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31#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A lightweight object and a very heavy object are sliding with equal speeds alongrf )*p 7)oo1lo,2r 3ratyg, mxhyj /-utqq6mp a level frictionless su3j 26yhxl1)ftoq) rr- r,oy pga ,m7/ot*puqmrface. 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 rs ;p +8gjxp pro,8f*:vc)sge$m_{1}$ 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 mechanica(.a6ev ay;ujcl energy for conservative forces.( 6ejuaca .yv;

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 air (7o.ow9 fjoz)wair friction is present), to the ground below. How does the kinetic energy (K) just before strik9)o w.owofz j7ing 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 gai1ia//u ny+j ymns 30 J of kinetic energy. Do not ignore air resistai 1ju /+/myanynce. How much gravitational 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 an4dl ;b*n(lw n4:ezv/gooig scr,4h +md loses 30 J of gravitational potential energy. Do not ignore air resistance. How much kinetic energy did the ball gainl z:siwrdnmgl4nv 4* 4b ;o,+eh(cg o/?

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 conse )..*ns(:pefsldl (ogxnp 5vnrvation 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 ise 5(( .46yuyfi j 5awk*viryej

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 ubv-q-ph.vu a7y w;a2u m(b8q enits?

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, whsiamt9. 3mi b5ich is 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, you did 3 times the work in one-third the time. To dvte o+;53r,fikqtaj vev+(k 2 o so, your power output must i+;e v+tart2(5v,ke k3 fvqjohave 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,cnz,nunvk:ru -*h 6n 1 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 +yyjbqgfi+6 virkk2 e25w*v)vertically 2.0 m and held there. If the object weighs 90 N, how much work w ey5ijq vyk*6vif2kw +g)+rb2as done in lifting it?

A. $360 \; J$

B. $180 \; J$

C. $90 \; J$

D. $0 \; J$

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44#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You lift a 10-N physics book up in the air a distance of 1.0 m, at a constant3roxhe8 ixue 2d8re3+ velocity of 0.50 m/s8re3ie +u 83d hxeor2x. What is the work done by the weight of the book?

A. +10 J

B. -10 J

C. +5.0 J

D. -5.0 J

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45#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 500-kg elevator is pulled upward with a constant force of 5500 N for a dvu9u z 1-jnlp 5p3py;zistance of 50.0 m. What is the p1z;59v3 un pylz-ujp 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 v ;,ec/. ugastupward with a constant force of 5500 N for a distance of 50.0 m. What is the work done by the weight of the ev ,cet; sagu/.levator?

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 forcvtth/xe*q12 qang( uv- 1; q/s1ls fbke of 5500 N for a distance of 50.0 m.1-t/u*st1 e2 v qb1;ghqlvf a/(qn xsk What 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 a/ w zgif2 vvsm.:cxb:q x:c,vd sq9.p.long 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 ai ;q40 3iubfwdt $30^{\circ}$ 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 icyh.rf) 5: 4ypz lg;zo6c my,)fjeaywn . surface (assume no friction), with a force of 60.0 N at agfzp:wafyjz)mc),;h rln y54. y 6.oen 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 in9t6kz:4y zv.vu ric9 g the direction of the force. The graph in Fig. 6-1 shows the force994cv krzziyt6:gu. v 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 in Fig*v2h *tw6s i70)yory8rp xzx b. 6-1 shows the force versus the object's position. riy8*r sbt) xxh6pwz7oy0 2v* Find the work done when the object moves from 2.0 to 4.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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53#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the fo:1rzei20kbt frce. The graph in Fig. 6-1 shows the force versus the objrfke b 0:ti21zect'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. Tvaxx.ag2n * 8ahe graph in Fig. 6-1 shows the force versus the object's positi xan82xg*va.aon. 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 is applizxw d/j 3s1f1vc 5;8gcu+x osmed to move a 55-kg cart (initially at rest) across a 10 m level surface. What is the finascg w;szvm3f 1/c81+jo udx5xl kinetic energy of the cart?

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

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

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

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

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56#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A horizontal force of 200 N is applied to move a 55-kg cart (initially4-9ztbkt.wpdxuo n591a f 1 kh at rest) across a 10 m level surface. What is the final1a.9-x thu4nptk1o5zd k9 fbw 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 oij *fi(xp:)2 kat bu7o09g wa 7nucl:ef 5.0 m/s. How much work is required to st:9cju*2pknu7)ie g tfxa(ali : w07boop the 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 s dt1h, .yun1feedhb7e8)b0uq top a car initially moving at 25 m/s, what distance is required to stop edbdqt1b.01,nyfuue h )7eh 8a 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 propels a 10-g dart. It is cockc ku66i -ipuwl f3y)* kpp1o:a zab2u8ed by exerting a force of 20 N over a distance of 5.0 cm. With what speed will the dart leave the gun, assuming the spring has n8 fu-k3ai :6c2 kwzaup obi )6y*upl1pegligible 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 5k f9ph(w(/a) f 2vnzafyz4vfvertical component of 60 N. The force is applied to a box which rf5a (fp9 /f(2nhv wzfy4kzv a)ests 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 byevjv19h 8mryj*ai 94 ale of hay, striking the hay with a velo9ery *iyhvv j41jm98 acity 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 moved from a height of 7.00 3vx) 9dqzf6*)t7) f svwwea stm above a floor to a height of 13.0 m above the floor. What is the change in gravitational pote)f6tewv)fs3* dtx w 9 z7s)aqvntial 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 risesaoc*+w xh5fip qf0o1 2 2.0 m. If the plane is frictionless, how much work was done by th0o+ ff*5a1h2oi p qxcwe push?

A. $1600 \; J$

B. $800 \; J$

C. $400 \; J$

D. $100 \; J$

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64#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-kg mass, hung onto a spring, causes the spring to stretch 2.0 cm. What is tbq2(i xqzf, rl8aa-4g u-mm1ihe spring constaqlm f4rui(xaa -b8 miqz1g -2,nt?

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 consfi1x: j51(f jgj1o k j-laez 7u)ardk-tant of 60 N/m. How much potential energy does it1x lu)kjaez(5jg11 difrj7 -fak -j o: store, when stretched by 1.0 cm?

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

B. $0.30 \; J$

C. $60 \; J$

D. $600 \; J$

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66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Calculate the work required to compress an initially uncompressed spring a*5)qnwx3ko+* y txiuwith a spring constant of 2 x*w a)kt3*x+i u5yqno5 N/m by 10 cm.

A. $0.10 \; J$

B. $0.13 \; J$

C. $0.17 \; J$

D. $0.25 \; J$

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67#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What work is required to stretch a spring of spring constant 40 N/m from x =i qx45ms)2n1j xw9oh l 0.20 m to 0.25 m? (Assume nmi xjw5x14sol)2q h9 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 infrgc1 nxh97x6/:mr tas1p.qhitially compressed by 3.0 cm. How much work is required to compress the spring an additxpn : 11rxrq/s7cgh 9ha.6mftional 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 res fb 3l9r ro5 ,e9nwbrqhp046evt from the top of a 50-m high slope. What is the speed of the,r b 5o40v 6hprf3br 9e9nwleq skier 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, plug7 s:/2n v v:e+gijvushes off the top of a hill with an initial speed of 4.0 m/s. Neglecting fr7g/v+ njei2 g: s:uvvliction, how fast will she be moving after dropping 10 m in elevation?

A. 7.3 m/s

B. 15 m/s

C. 49 m/s

D. 196 m/s

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71#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object slides down axmz o hzmaa+f86a51x( frictionless inclined plane. At the bottom, it has a speed of 9.80 m/s. What is the vertical heightxmx5azz8ao f(a6h1 + m 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 thc d0mr3mf ,n);f*ff fpe floor, its potential ener ;,fm*p0f r)nc mdf3ffgy exactly equals its kinetic energy. How fast is it moving?

A. 3.7 m/s

B. 6.9 m/s

C. 14 m/s

D. 45 m/s

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73#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A toy rocket, weighing 10 N, blasts sc plc(5x9gfc9pzw 9yt 7bk5b (traight up from ground level with a kinetic energy of 40 J. At the exact top of its trajectory, its total mechanical energy is 140 J. To what vertical height doeb( 9g7 ( zc5 lyk9fcbx59tpwcps 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. At them /vcaq trp+8/ hic /rq+tp 8vma/ghest point in its trajectory, its kinetic energy 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 the bottom bs+3ltvk08kw 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 bottom of thes8tb3k0+vwk l 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 me t 6 qzr3wa0-6, 8(jwtbrj:kzz-ymut/s at a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed 0r6 r3w tjz,w:jt ba zyk(-u6qetm -8zof 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 abo gdg6;*z) au1kv0(uaij39 vt9fvbvp rve the 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 9 gp g91a uvk(*ra6 f;jb t0duv)3vzvitop 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 bottomyv ljzh84uo.m) z514e: ltc bb 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 0.21 m away ;1zheoowhodm//-ry r+q;+ep yp9: qafrom the vertical axis and released from rest. What will be hooh dw+/r;/zp; ypoqma e e9r-q1+y: its speed at the bottom of its swing?

A. 0.2856 m/s

B. 0.762 m/s

C. 1.142 m/s

D. 0.952 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 ( bnsa-t nsde84hg 5c/hits an initially uncompressed horizontal spring with spring consta5bda8(h4-c gtn/ s nsent 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/ss36vpn +bw 2ld+7ep lg;uyv/ x, slows down her 2000 kg car to stop for a red light. What wes7dg6b2+xn w3pl; vyv/p+u lork is done by the friction force against the wheels?

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

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

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

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

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84#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The kinetic friction force between a 60.0-kg object and a horizontal surface isex0p068jri gl* up uo4 50.0 N. If the l*ux 8o e00pp6ig4rujinitial 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 e,sx): 4tbq:k)vjx xwlnergy. The friction force on it is a constant 0.50 N. How far will it sli sxv,k::xq)4jlx b)w tde?

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 applae 2e7yy5xqg y)xr8g7qg;4haied horizontally to a 2.0-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 ch 4yexxg qy5ygq; 7 ga)27ea8rhange 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/+m; u)bwk7m6eymo cu,a kf :h of a 50-m high slope. If the work done by f6uhk ;mk7obm /a:c wm)+ye u,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 pushex -7 hjy 3ba9q4vyz3zfd up an inclined 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 o3- 3by9avjzq fxh7 yz4f 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 inclined at 20ezf(ug6*syanpt: 9bu9 above horizontal. The coefficient of kinetic friction between the mass and the plane is 0.20. What will be the speed of the mass after sliding 4.0 m along thegfu(*zp:s n9ay9bu 6t 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 strikcx6ljlcz:;,*pn4( s8 a l)umayeb: fk es the ground with a velocity of 7.0zbel8 y)j ,4; uc aa kp:flm(xcl*6n:s0 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 fl90 pbnv+tw ,gwgu(1izight of stairs 10.0-m hit9bui0g 1 nwg+v zpw,(gh, 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 w .ml7n6o zh0fzith a constant velocity of 5.0 m/s. Whaz0nm7 zloh.f 6t power must be delivered to the object by the force?

A. $0.50 \; W$

B. $1.0 \; W$

C. $50 \; W$

D. $100 \; W$

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93#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

How many joules of energy are used by a . dwilbsk egr8t;p3mn61 fi5s,gd8 3g1.0 hp motor that runs for 1.0 hr? (1 hp = 746 W)38md fsn.wkdgs b81 e,5gp gl3i ;rt6i

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 t 9hjr afmt)( g;z1oqy)he rate of 500 W while riding. How much force does her foot push with jm)rhzqa;)91fty(og 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 fr r. wexhyr7/guat.a.3om 0 to 25 m/s in 7.0 s. What is the average power de wr.ury 3.a./etag 7hxlivered by the engine? (1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87	88	89	90
91	92	93	94	95