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

1#

What is the correct unitn z,mo/-.rd rv of work 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 sy)qetdxy:;419r wcg v ig 4is*lstem 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 statio b4:7bch x g (02cclibe2:gfaunary brick wall, the amount of work youg2e fi(cbcxc 2 bb7h:ul:04ag 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 there. How muchp(*u7n k 93+ynycier h work is beingye n7(hc *3n9rukpy i+ done in holding the box in this position?

A. more than 100 J

B. 100 J

C. less than 100 J, but more than 0 J

D. 0 J

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5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you walk 5.0 m horizonp8 /s7g:y aqiqhh8b7x tally forward at a constant velocity carrying a 10-N object, the amount of work you d88 /sqp:qgiyaxbh7 7h 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 2zojlpy k)*a 1lifted vertically 3.0 m then returned to its original posit j 2kz1p)*yaolion. 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 centripetal force acting on an obj6:ry ,vbink+t ,*hldzsj b+0pect 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 gra zp lfdy,25xttg 4a(+dvity while the ball goes up with the sy (dz5ptgaf xd+4tl, 2ign 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, on a Force versus position (F vs. x) graph,nf2eml8s .wh7i/, ,whj 6xzfs representsi l6ms/hsjww.z 8 fe2fhx,n7,

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 ve*m dm ,1r;jxpzrsus position (F vs. x), what represents the work done by the f,1jmmp;dr*z x orce 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 tx)u r8rbh c7ccf+2iu r7yz/*k4 qfnz-he 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 obm :bre a12dg/zx*mj3n ject is negative, then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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14#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an obja(bm+l ab9, mkect is zero, then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A truck weighs twice as much g+jks+dt15b x7-rile as a car, and is moving at twice the speed of the car. Which statement is true about the truck's kd1k-br75 l+gt i+esjxinetic energy compared to that of the car?

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

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

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

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

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16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Car J moves twice as fast as car K, and car k ;+j xtkajx7-J has half the mass of car K. The kine xk;-+jjtka7 xtic 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 back with half ofb70 d(j.a tu wp30uztj its original speed. What is the ratio of the fin u0 batd3z( j0pwtj7u.al 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 movi),n/jtqki 1( b ogstji3vb6+b ng at a speed of 5 m/s. If both objects have the same kinetic energy, what is the ratio of the brick's mass to the rock's mass)bg+/3 6j,ti nktv1oj bsi(b q?

A. 25 to 9

B. 5 to 3

C. 12.5 to 4.5

D. 3 to 5

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19#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.0-kg mass is moving with speed 2.0 m/s. A 1.0-kg mass is moving with speed /9plsjn/sc2 u4.0 m/s. Both objects encounter the same constant braking force, an/29lps ns/cuj d 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 env+ kda,tn,. rajrtf3o z6:8of your car in a panic, and skid a certain distance on a straight, level road. If you had been traveling twice jrta3dokvn+ t,na f6e,. z :8ras fast, what distance would the car have skidded, under the same conditions?

A. It would have skidded 4 times farther.

B. It would have skidded twice as far.

C. It would have skidded 1.4 times farther.

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

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A planet of constant mass orbits the Sun in an elliptical orbit. Neglecting: *gzvl09tbmbyx4me:lg -x(f any friction effects, whfy(xg:b vez tl:mg-90 4*mlxb at 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 princi 1ewv8h /;71gzrpwzwmple.

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 negative potenti9 iv j-6j1 br4ppq n+*ykq-qieal energy?

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

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

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

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

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26#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object is released from rest a height h above the ground. A second objem92 lc)6 /:l;ab e0kuowg7ib wgvk fu2ct with four times the mass of the first if released froewl)i b 9cb mw2o/gu6;7ak02kfg u: vlm 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 causes it to stretch 5.z5 wlobtqd1 u 4k:)3ur0 cm. If another 0.200-kg mass is added to the spring, the potential energy of dlt qu :k1wb) 54uor3zthe 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 ebdzpy fwo*7:k-2( l-z r4i bwinergy 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 K, to it 0nxunb e/0s2w2 dim;y*ei7rys potential energyi020 ; *neenbu/wyrdx7 y is2m 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. 2c+jo4 gwopr1fk6jr. 8k)fvi

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*sdt 4u7q*/rl3ofh5 r;odv )z zca- lo a very heavy object are sliding with equal speeds along a level frictionless surface. They both slide ur /dr-h ;)d5s *3qlftz 4 z7aooluv*cop 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 .bckol ocbjk,zi)m3 2 a 49;kk$m_{1}$ and $m_{2}$ at the top of two frictionless inclined planes. Both masses start from rest at the same height. However, the plane on which $m_{1}$ sits is at an angle of $30^{\circ}$ with the horizontal, while the plane on which $m_{2}$ sits is at $60^{\circ}$. If the masses are released, which is going faster at the bottom of its plane?

A. $m_{1}$

B. $m_{2}$

C. They both are going the same speed.

D. cannot be determined without knowing the masses

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33#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the principle of conservation of mechanical energy for con9 do9t( pikqw56*wb:-h-pu6dbbi ewuq8 gu: v servative forces.6pep d - v*ii9 w8wqwb :5u9od b(tku:h-qbg6u

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 (aired:u iwm4g:94bq 5xdy friction is present), to the ground below. How dbd5u :xy 4eg:im49wdq oes 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 kinetic energy. vps)y y 63js,bDo not ignore air resistance. How much gravitational potential energy di,sp 3 yy6bvj)sd 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 energy. Dwix vz30q 5,lyrba(yy ( 9vea;o not ignore air resistance. How much kinetic energy did thyib xylw5y a(3z;0q (e,var 9ve 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 conserte 11 n;7pgp6dfv rt8iv/v8byvation 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 isj dave zw 5(3ob6+wvu18auk4z

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 vko+cwgt.e0d2c .*d w 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 8q d:mjk*1s1f -xi;zsxbgln7unit 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 one046-xljqn ojvf//j iz -third the time. To do so, your power outpu - n i/jjlz4vq06/xjfot 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 constant acceleratif)o6nujchxm ,n s;0zpcb*c3h *jk f9*on, 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 thbtj y0 vq6fb/,.yh4hi e object weighs 90 N, how much work i,bt h/hyyf.0v4q jb6was 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 b:ru-o)ik 2 ejqr-m7e nook 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 of k r2niu )oemr:jq-e-7 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 puall a;:nq(:es lled upward with a constant force of 5500 N for a distance of 50.0 m. What is then;(e a:s qlal: 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 w7y8t97zo 5na4,un..jye(f aqx yf owyith a constant force of 5500 N for a distance of 50.0 m. What is the work done by the weight afyyj f8n 9,u 54.nw tyqzx7.o(y aoe7of 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 conyz a :hj8(no7n )ee(elstant force of 5500 N for a distance of 50.0 m. What is the net work (e: )z8ajl(nyhnoee 7 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 mz bmaj/r/em, 0t4eqs - up along a $37^{\circ}$ inclined plane. What is the work done by the weight (gravitational force) of the box?

A. $-11 \; J$

B. $-1.1 \times 10^{2} \; J$

C. $-1.4 \times 10^{2} \; J$

D. $-1.8 \times 10^{2} \; J$

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49#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.00-kg box of fruit slidm:;wmkckqth1 y8g6:des 8.0 m down a ramp, inclined at $30^{\circ}$ from the horizontal. If the box slides at a constant velocity of 5.00 m/s, what is the work done by the weight of the box?

A. $157 \; J$

B. $-157 \; J + 78.4 \; J$

C. $78.4 \; J$

D. $-78.4 \; J$

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50#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Matthew pulls his little sister Sarah in a sled on+de g r,gsv2asi. pl9x)ki-s9 an icy surface (assume no friction), with a force of 6)ega+9sk pxdilg-2, 9 rv.si s0.0 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 forrm ;shi/ 7:87axx 5lpn:f pnhwce. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves :wh mpl5xfhxp:n 8n ia;77rs/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 gr g0nint **oto)b+ mvp ut:q.7aaph in Fig. 6-1 shov7 gmin u+ptq)oo. *n b0*:ttaws the force versus the object's position. Find the work done when the object moves from 2.0 to 4.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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53#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the fo iphd 5c.jj)m(kve;y 7rce. The graph in Fig. 6-1 sh.7v m;p(c)ki 5jj ehdyows the force versus the object's position. Find the work done when the object moves from 4.0 to 6.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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54#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the force. The gtikei2vk9c84m3mrei-p* .hd5z mg9 praph in Fig. 6-1 shows the force versus the object's position. Find the work 3g 95eppk8 diiz9rm mm-ihk*c2vet4 . done when the object moves from 0 to 6.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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55#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A horizontal force of 200 N is applied to mop5sh 2clq7y3hve a 55-kg cart (initially at rest) across a 10 m level surface. What is t3shc 2hpqyl 57he final kinetic energy of the cart?

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

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

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

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

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56#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A horizontal force of 200 N is applied to mov kc0rhav5nj, w5p69pd e a 55-kg cart (initially at rest) across a 10 m levhk0p, 65ar wnd5jv9c pel 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 movindiq. * 3eqkf2ug with a speed of 5.0 m/s. How much work is required to stop the massif.eq uqkd3 2*?

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 yxgix:x-x /2xinitially moving at 25 m/s, what distance is required to stop a car moving at 50 m/sg-x:ix/2 x xyx 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 proy2d0t oo.iqz4;m v) 29hghn sdpels 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 leave the gun, asmzihq t2 . )g4sv;09yod dho2nsuming 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 comfoyb*wq-,l y n*f z6n 5wq.6nhponent 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 horizontally along the f .* ly qqw n56nbw,oh6y-f*znfloor. 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 horizontallyp7xd:o r/5 b9i8rdy oz into a bale of hay, striking the hay with a velocity of 60 m/s. It penetrates a depth of 20 cm before rp9/:5d oy idrxob 7z8stopping. 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 a6xbku.xri.5yy q/e -r 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 en.bix ry ye-.5u/rk6xq ergy?

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 inc2bhd7s c,j1jvyo3l8s lined plane. The plane is 4.0 m long and rises 2.0 m1bj3c 7ljvs8 hd2s,yo. If the plane is frictionless, how much work was done by the push?

A. $1600 \; J$

B. $800 \; J$

C. $400 \; J$

D. $100 \; J$

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64#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-kg mass, hung onto a spring, causes the spring to st,huhf q 49 ax8fn8a9nvretch 2.0 cm. What is the spring confn 9q48x f9a8u h,hanvstant?

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 characterizc+s)ji st/m+7*ri*rqepth. r ed by a spring constant of 60 N/m. How much potential energy drrtis*+/r+.7 chmqe*t j is)poes it store, when stretched by 1.0 cm?

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

B. $0.30 \; J$

C. $60 \; J$

D. $600 \; J$

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66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Calculate the work required)-e;,sjajisv pa;;i9 la fc7i to compress an initially uncompressed spring with a spring constant jcap sf; ,a;lai- v97)sjiie;of 25 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 fr ,r;6 hn6iyf*m88hwc hn6bj khom x = 0.20b; *66jhm8 h6yfcnik8w,rn hh m to 0.25 m? (Assume the unstretched position is at x = 0.)

A. $0.45 \; J$

B. $0.80 \; J$

C. $1.3 \; J$

D. $0.050 \; J$

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68#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring with a spring constant ofd9 suyea81fk.6 *ehwyy8 h pie67wt9y 15 N/m is initially compressed by 3.0 cm. How much work is required to compress 96yh yeawtdu7w y1*88h9 fkp.e6iys ethe 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 slope. Wha mv+hieyvu-gkay d6 2)u r*1q5t is the speed of the su2v) rd*q-1egy ay hk6i+5mu vlier on reaching the bottom of the slope? (Neglect friction.)

A. 22 m/s

B. 31 m/s

C. 9.8 m/s

D. 41 m/s

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70#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A skier, of mass 40 kg, pushes off the top of a hill with anlk7 fk7os)nwh/1 j4i,o16y8vxfu rxv initial speed of 4.0 m/s. Neglecting friction, how fast will swl kk4716,x8ovv17 ouyhsjxiff) rn /he 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 a frictionlesok3gcc0 w8c ph-t2l ;js inclined plane. At the bottom, it has a speed of 9.t 8;gwkhcoc -0 23lcjp80 m/s. What is the vertical height of the plane?

A. $19.6 \; m$

B. $9.80 \; m$

C. $4.90 \; m$

D. $2.45 \; m$

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72#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1.0-kg ball falls to the floor. c/k/e4/w/yu;e a ynxfzrp:i.hu2 /tw When it is 0.70 m above the floor, its potential energy exactly equals its kinetic energy. How fast isfwy/ieutraw exycn 2;h/ k//u4/:z.p 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 straight 8an,8bdvmh *mup 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 heib8mva8*nm ,dhght 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 mmhu1lu, zrb 44 leaves the ground with a kinetic energy of 220 J. At the z1u4uhlm, b4r highest 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 rev(m wg: xs-e ut;gllil ta)f;w9 9n;2bst 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 x:btfa9 vl;i9t;; lnw(s-)e2g mulwg, which is 30 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 17 m/s

C. 24 m/s

D. 30 m/s

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76#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster starts with a speed of 5.0 m/s at a point 45 m above the x2q0g 1cnik(l bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed o0nqx(i k1l gc2f the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?

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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 l)v16ci5 ncizm above 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 z1 )6cvnli5ci at the top of the next slope, which is 45 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 16 m/s

C. 18 m/s

D. 20 m/s

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78#

( 1.0 分) 切至整卷模式搜藏此题

What is the minimum speed of the ball at the bottom of its swing (p3d;pej4wdg g* oint

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79#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A:2.2 m/s

A. 3.1 m/s

B. 4.4 m/s

C. 4.9 m/s

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80#

( 1.0 分) 切至整卷模式搜藏此题

难度:2

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81#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A pendulum of length 50 cm is pulled 30 cm away from the bcn8qj n.d4g :vertical axis and released from rest. W 8n dq.bc4jg:nhat will be its speed at the bottom of its swing?

A. 0.50 m/s

B. 0.79 m/s

C. 1.2 m/s

D. 1.4 m/s

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82#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1500-kg car moving at 25 m/s hits an initially uncompressed horizontal spriet*iigknbs .:*d0+xt8; w r6a le zot2ng with spring constant of kleab.+;z*go t8srd6tt*:i n20 ewix $2.0 \times 10^6 \; N/m$. What is the maximum compression of the spring? (Neglect the mass of the spring.)

A. $0.17 \; m$

B. $0.34 \; m$

C. $0.51 \; m$

D. $0.68 \; m$

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83#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A driver, traveling at 22 m/s, slows down her 2000 kg car to stop s xhi-g78c3r )azmu*q for a red light. What work is done by the friction forrmu cih-z7 *a)q8 gxs3ce 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 obxnzcehv;) 8j /ject and a horizontal surface is 50.0 N. If the initial speed of the object is 25j c8 xzn;v/h)e.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 movinue8pj:(ui4k+ ty) vxnl;ae tt**6srf g on a rough, level surface. It has 24 J of kinetic energy. The friction for4)yv*8 itet;ufsrt6+x*k:ual jpe(n ce on it is a constant 0.50 N. How far will it slide?

A. $2.0 \; m$

B. $12 \; m$

C. $24 \; m$

D. $48 \; m$

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86#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force of 10 N is applied horizontally to a 2.0-kg mass on a le4oz(bskf: 8dq/ ; bkadvel surface. The coefficient of kinetic frictk4fk:/ 8(bd a;zsoqdbion between the mass and the surface is 0.20. If the mass is moved a distance of 10 m, what is the change in its kinetic energy?

A. $20 \; J$

B. $39 \; J$

C. $46 \; J$

D. $61 \; J$

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87#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 60-kg skier starts from rest from the top of a 50 a;c8xda;t *rp-m high slope. If the work d8r*pat; x;a cdone by friction is $-6.0 \times 10^{3} \; J$, what is the speed of the skier on reaching the bottom of the slope?

A. 17 m/s

B. 24 m/s

C. 34 m/s

D. 31 m/s

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88#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An 800-N box is pushed up an inclined plane. The plane is 4.0 m long andfff- i6(ht zm/ 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 averi(6z fh/ -tffmage 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 20e abovag(n jgh, 0 ki51ejj;lhqu63b 6szv nv7p od.-e horizontal. The coefficient of kinetic friction between the mass and the plane a0p kh3 ei ds,n6j5 (u 1;bh7qvzojlg6jg.v -nis 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 strike7r8m pu :h g/plom9b;l8/jdrts the ground with a velocity of 7.0ro:l;b9m/8d7grp tuh/ l m8pj0 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 he1(-j 56v cqaguwo a.rd runs up a flight of stairs 10.0-m high, inw q acr1 j6o.(u-adg5v
8.00 s?

A. $75.0 \; W$

B. $735 \; W$

C. $4.80 \; kW$

D. $48 \; W$

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92#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-N force is needed to move an object with a constant v+8vc(g vk8e+ nm twjh3elocity of 5.0 m/s. What power must be delivered to the obvtm+w+8h8ev( jg cnk3ject 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 2aldcyu5fbvk:vnh(0r 1hgji:2 7q8l 1.0 hp motor that runs for 1.0 hr? (1 hp = yicqgk5n71ll:av 2b0j v2 :h8(urfh d746 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 wx8vrv9awi4 8l udnn n;z *x0 7)j)iccthe rate of 500 W while riding. How much force does her foot push with i)n w9c4w; v8*8)rzvduxjail nn0c7xwhen 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 averagej0 c isch9 ;b6v,j9hih power delivered by the engine? (1 hp9,;90hhjc6bv iishcj = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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