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

1#

What is the correct unit of work expressed in SI unit6u3hyvst.rio c:ruy,eip3 w *;ov92 rs?

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 syn93(w sbv(ra* q9pf xo/oi (uhstem 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 hlwk+5s9g )u7p g+njff4krj4 h- l;d qbard against a stationary brick wall, the amount of work you dpk+jq)hd sfn4 u rklg5fl 79g+bwj-;4o

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./o3qi-m*pck(:. w j*ilhq zyv0 m vertically and is being held there. How much work is being done in holding the box in t mqi*(-j/yk3. vio: wqzpcl*hhis 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 velocxkoy5) ywm(x)qkf4z w 8t8 )srity carrying a 10-N object, q mk)fkysx 4 )z8wwy )tr5(ox8the 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 3.0 m thep9,b9mv;i 1swcgr n vr*a6st mpx0 j7,n returned to its original position. If the total weight is 30 N, how much work was done1t,pgxr ;s9 6 cmnjrb,w9 pi0s7v* avm?

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 3s39hacu6lfg p j7 bx,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 gravity whi4- h ae4)daa5281r h sapdwkgmle the ball goes up with the sign of the a28-aa44ga)w kh 5rp1em hsddwork 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 q ipb0-juq-u(f /lo91f* vd hfvs. x) graph, representsvp0 9/u(qfdu-* -foil 1bfqjh

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), wd7wvl+u; zx.1nn 9mr;iw kiv5hat represents the work done by the force wv.7z1v km inn5ri; lxd+;w9uF?

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 positive64j*qynlca69vw) dn9q bh0e c, 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 kinetio un.ra*)q i(jjc)8lgc 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 3s.ov.,qpv t2:y0n1ktj rk zyobject 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 as a car, and is moving at twice the speedtr,wh;zp o/ 6h sx0l+q of the car. Which statement is true about6+spqxl wz, ho; 0rh/t the truck's kinetic energy compared to that of the car?

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

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

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

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

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16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Car J moves twice as fast as car K, and car J has ha lze+ fqghwj1z : c84hm+bdb8:lf the mass of car K. The kinetic energy of car J, compared to 8h:b:w jhgezflcbmd+ q4z+18 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 wx 3apsb+afd +xy6f:dt kvm 9gxj8 z,*5ith half of its original speed. What is the ratio of *tv, 9axmfzy+sjg:f+xdbp6da58x3 k 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 o6*lqkx7 n q:q3 m/s and a pebble is moving at a speed of 5 m/s. If both object7qxql:n6 *k qos have the same kinetic energy, what is the ratio of the brick's mass to the rock's mass?

A. 25 to 9

B. 5 to 3

C. 12.5 to 4.5

D. 3 to 5

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19#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.0-kg mass is moving with speed 2.0 m/s. o5 ofa29xapw ,kk5 q(pA 1.0-kg mass is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to res2 kak(,5ofpxqao9pw5 t. 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 ski. 5)d uqodl+tdqb f1q2d a certain distance on a straight, level road. If you had been traveling twice as fast, what distanc 1bfqq 2d)lot.dq+u5d e 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 elorwq. b/(o srfs6 ;s 8sxbm0rab.r3t +liptical orbit. Neglecting any friction effects, what happens to the p.orq./ f(t a 8x+w03sbmb6bsr sr;orslanet'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 - m;cfweo- +s.r xf 2r0ceow(zprinciple.

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 ha*92mk9hsa 6mxb j+ jz+ gr;awgve 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 a height h above the ground. A seco fzj34h,wl *khnd object with four times the mass of the first if released from the same height. The potential energy of the second object compared to3hz khlfj,w *4 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 j,.;vr b;ncn ti (jlg/of a spring causes it to stretch 5.0 cm. If another tjn;l( /vj., bci;gnr0.200-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 b;qx h3(v ty+ yz/g/iwyn0-/9qasr ekenergy 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 tx:bnit j yzi.k7k:/5 jree. Compare its kinetic energy K, to its potential energykt7 injx:kb :z/yi 5j. 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 o o w3flh68n)7q pqs(nff 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 7bfwn,s 2:sqdf*a6 tzqvr, t1are sliding with equal speeds along a level frictionless surface. q1 frt twvs,6n:q*,z saf2d7b 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 cj1rckq g3v -;gg.p 8tfqb2y1$m_{1}$ 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 mechaaft7ullsq1 8d, (5oj inical energy for conservative forcesl8,s7j5(ulq 1fo tiad.

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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 (air friction is w.;l0bjo l ur:o7,le;c4 qnvj dich7. present), to the ground below. How ;w;lo0joqdlc n. c7.h,ij4ve7r ulb : does the kinetic energy (K) just before striking the ground compare to the potential energy (U) at the top of the building?

A. K is equal to U.

B. K is greater than U.

C. K is less than U.

D. It is impossible to tell.

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35#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A ball drops some disxujo)daeyw s4d2x452ys ,x( vtance and gains 30 J of kinetic energy. Do not ignore air resistance. How much gravd4 x5ey v4,22d(syxjoxuasw)itational potential energy did the ball lose?

A. more than 30 J

B. exactly 30 J

C. less than 30 J

D. cannot be determined from the information given

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36#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A ball drops some distance and loses 30 J of gravitational potential energy0s( v, vvltrd:lh5l8tc6 v uu*. Do not ignore air resistance.tv*lrl 85 th:s0 vuldvv(u6c, How much kinetic energy did the ball gain?

A. more than 30 J

B. exactly 30 J

C. less than 30 J

D. cannot be determined from the information given

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37#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the law of conservation 7c-qncw:ob - xbxlv5; of energy.

该题自我估分: (必填) (满分:1.0分)

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38#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity Fd/t is*vk9feu -/m2f(ria 0nr(zfei

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 exprezx.k.z mp b24lssed 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, whiojxsqcm )3;r) u-qt) box0w8ech 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. T:v4e,d g)hkzqx7 u1gv o do so, your power output muskq :hegudz ,v7)4vgx1t 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 car's engpcy92mz v +b9oine 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 wel gj8(8cb*m aa m,rlt0ighs 90 N, how much work was done in l 8g,a0ratmblc8 (l*jmifting 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 2w mi+bzar( a4of 1.0 m, at a constant velociaz+ (42 rwmabity of 0.50 m/s. 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 cons- z1(ucrg,qho tant force of 5500 N for a distance of 50.0 m. What is the work done by the 5500 N uo(,cgqr-hz1 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 consta j2jll xwnm,37nt force of 5500 N for a distance of 50.0 m. What ism3 j,jl2 wxl7n the work done by the weight of the elevator?

A. $2.75 \times 10^{5} \; J$

B. $-2.45 \times 10^{5} \; J$

C. $3.00 \times 10^{4} \; J$

D. $-5.20 \times 10^{5} \; J$

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47#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 500-kg elevator is pul++ qsb,: n(spsa. lke 2o0vvhtled upward with a constant force of 5500 N for a distance of 50.0 m. What is the net wor:v. +2e,0hk vt sp(slnbqosa +k 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 emt*6 s. key+qup 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 slides 8.0 m down,gfv/zc7jo )adl ;3ic 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 an icy surface (assume no friqbtl91brd;xo8n tq9)ction), with a force of 60.0 N a8bqb n1 ox; tlrdq9)9tt 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 ofnw6;r f-ulfyg.q+f wy m1 tg51 the force. The graph in Fig. 6-1 shows the force versus the object's position. mr lwy ff.t; qn1 f5w1ug-gy+6Find 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.(g.+gb qw vjxrs.cy 2; The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves from cs+ r2.yq .bj;(wgv gx2.0 to 4.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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53#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the force. The gragwk3hbky4.k bc d8:g;ph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object move.kb8bkhgg4 ;ck: wd 3ys 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 iel6.s hgr*w *nn the direction of the force. The graph in Fig. 6-1 shows the force vesl6*.ewhr n* grsus the object's position. Find the work done when the object moves from 0 to 6.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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55#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A horizontal force of 200 N is applied to move a 55-kg catbc5a80t*q f jrt (initially at rest) across a 10 m levt8a 5b t*c0jqfel 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 applied to move a 55-km ays3r-jrf /q(jnd6 (7mm fun64pj4mg cart (initially at rest) acrosqu6(n46/ j d7jmn3j4 p mmmfar yrs(f-s a 10 m level surface. What is the final speed of the cart?

A. 73 m/s

B. 36 m/s

C. 8.5 m/s

D. 6.0 m/s

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57#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-kg mass is moving with a speed of 5.0 m/s. How muc v2t1 zfk6owe.h work is required to stop the mat1 .wo zfk6v2ess?

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 re pggc,, son*p0vesvv1hd 2+u :quvn:po+sv,c2 d0gsep,*v 1 hguired to stop a 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 propels133m8pgo 9 q;e3 lhud8zmpltu 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 thhz ;tm u8d 39oqmp ple38lu1g3e dart leave the gun, assuming the spring has negligible mass?

A. 10 m/s

B. 14 m/s

C. 17 m/s

D. 20 m/s

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60#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 100-N force has a horizontal component of 80 N and a vertical compob;le1 ,a xax i8pc5dives+znls5: 3s.nent of 60 N. The force is applied to a box which rests on a level f.5dxbaess;: s,z i51i+lvpel3 acx8n rictionless 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 i p:8g/el6q46ydzkgf anto a bale of hay, striking the hay with a velocity of 60 m/s. It penetrates a depth of 20 cm before stopping. What is the average sq6kefd la4 g/p6:8gz ytopping 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 lc1f c cem/)(ak+ewk q-6ki2z+j m*rl 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 potenc* kwfl i+c2/ rezcqmej-km6a+)k (1ltial 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. *6)xnt3wh( p tg7c/p luv* mncThe plane is 4.0 m long and rises 2.0 m. If the plane is frictionless, how m3x6cnu7cv ntg*(pp/t)h lw*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 onth6df ,tes0, lyo a spring, causes the spring to stretch 2.0 cm. What is the spring 0 ylh6dtfe,s,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 muchi)uptleff1-( qf / +sz potential energy does it store, u+ ts q)z(fil/fp- f1ewhen 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 tocbl nj;:sw-fgn c j3nr/n:u8) compress an initially uncompressed spring with a spring constant of 25 n8njg bcf nljc :3r)s/nw;:u- 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 strlxs e-l0q 1kk :o9qh ;xu2cfn+etch a spring of spring constant 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretched position isf1cq+ukx9l :0 x qesn l;o-h2k at x = 0.)

A. $0.45 \; J$

B. $0.80 \; J$

C. $1.3 \; J$

D. $0.050 \; J$

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68#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring with a spring constant of 15 N/m is initially compressed by2fcq d+o :b7slu ,oej2 3.0 cm. How much work is required to compress tb2,l f+sd qjeo27o:uc he 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 f.*f a/wb,yd+.basbwh rom rest from the top of a 50-m high slope. What is the speedf.+byhs,d wbbw.* /aa of the slier 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, pushe-cictb 7e uhiw/ +ae,r,4 ufau *s(:gys off the top of a hill with an initial speed of 4.0 m/s. Neglecting frictiont uwch/* iye ,u:-re4 c(fau,ib7g+sa, 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 a 35ev.p hfr5lefrictionless inclined plane. At the bottom, it has a speed of 9.80 m/s. What is the vertical height o3ferl5eh.v5 pf the plane?

A. $19.6 \; m$

B. $9.80 \; m$

C. $4.90 \; m$

D. $2.45 \; m$

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72#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1.0-kg ball falls to the floor. When it is 0.70 m above the floor, i dtpo*k5z 3hj)ts potential energy exactly equals its kinetic energy. How fast is it moving5ht3* j)dpzko ?

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 from ground levdz8f y68 seq)hel with a kinetic8 fse6 hqy8z)d energy of 40 J. At the exact top of its trajectory, its total mechanical energy is 140 J. To what vertical height does it rise?

A. $1.0 \; m$

B. $10 \; m$

C. $14 \; m$

D. $24 \; m$

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74#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A projectile of mass m leaves the ground with a kinetic energy of 2203c4 w)azg;*n:vm r vpg J. At the highest point in its trajectory, its kinetic energy is 120 J. To what vertic ngr*4:v;cam3 pvwzg)al 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 startszman.bs2v1ldv., u) s from rest at a point 45 m above the bottom of a dip (See Fig. 6-2). . vz.1sv)s2 dlu,bmnaNeglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?

本题所包含的其它图片:

A. 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 therwf*d lz;x 6 qxir(9l9 bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top owi ;f6d*lxr(z9qrl9 xf 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 poie3;zh1b xbuz, nt 30 m above the bottom of a dip with a speed of 25 m/s (See Fig. 6-2). Neglect friction,bzhbze;3xu, 1 what will be the speed of the roller coaster at the top of the next slope, which is 45 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 16 m/s

C. 18 m/s

D. 20 m/s

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78#

( 1.0 分) 切至整卷模式搜藏此题

What is the minimum speed of the ball at the bo6 cya331gs(h-0m b.vy mpz dngttom 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 pendulum of length 50 cm is pulled 30 cm away fr0t2gri*rp/wr-a i sd) om the vertical axis and released from rest. What will be its speed at the bottom of itapi*-ir0 )drg /ts2 rws 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 hitsjw: n j.(;qpxss06s gq an initially uncompressed horizontal spring with spring cossjjq: ;.spqx0(w 6gnnstant of $2.0 \times 10^6 \; N/m$. What is the maximum compression of the spring? (Neglect the mass of the spring.)

A. $0.17 \; m$

B. $0.34 \; m$

C. $0.51 \; m$

D. $0.68 \; m$

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83#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A driver, traveling at 22 m/s, slows down her 20)mh*ktc0 h2t/scr)cp 00 kg car to stop for a red light. What work is prc)c) ks/tcth20 m*hdone 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 ho.4 upm72dlpfc+v; f mn)xo1aza02j ldrizontal surface is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will)xdoj p pmu0fcala+. v427fm n;2z1dl 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 ,k)k3q.an g57ejj nyj a rough, level surface. It has 24 J of kinetic energy. The friction force on it is a constant 0.5.73nq)yka jjej,n5 kg0 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 level3l rybtova ,k+g*/n.x surface. The coefficient of kinetic friction between the mass and the surface3rkx*l + vtba/oy.n, g 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 uu(ra* w(i8-,)jh3 dlxrty 8r2wf ntu top of a 50-m high slope. If the work done by friw2n wa()uu 8-ltr x(rjyru,*ht3id8fction 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 planes+qpr4t7i0qt 27ja chl)hx: x. 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 taxlqt+2pcjhh07tq4x:7 r) ishe plane. What was the magnitude of the average friction force on the box?

A. $0 \; N$

B. non-zero, but less than 400 N

C. $400 \; N$

D. greater than 400 N

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89#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2.0-kg mass is released from rest at the top of a plane inclined at 20,izx fpn/tl1a.x,w1u6g d1ws w - aaz17q oy5le above horizontal. The coefficient of kinetic friction between the mass and the plane is 0.20. What will be the speed twala 11-l. ,dwixxq7/5nygso1fpwu 16 z ,azof 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 -r )mm0d 9my5 pdjduf4m, and strikes the ground with a velocity of 7.00 m/s. What average forc4r y- u9dmfd 5jp)m0dme of air friction acts on it as it falls?

A. $22.5 \; N$

B. $75.0 \; N$

C. $225 \; N$

D. $293 \; N$

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91#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

At what rate is a 60.0-kg boy using energy when he runs up a flight of stairs*tdxfi hy, x/p4 f:c)o 10.0-m xpt4*ixh:,/cf fo d)yhigh, 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 cgsljk(;tm, *ad:bb+ukbi 7o)onstant velocity of 5.0 m/s. What power must be delivered :ak,td7* ( guo; m)klbbbji+sto 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 used5p7m* ohy(xb;u u*lxbo )9upw by a 1.0 hp motor that runs for 1.0 hr? (1 hp = 7u) ou7 *b* yx;pumx(9bwpoh5l46 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. Hov06 dlki w)m5qw much force does her foot pushm0w5q6ldv ik) with when she is traveling at 8.0 m/s?

A. $31 \; N$

B. $63 \; N$

C. $80 \; N$

D. $4000 \; N$

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95#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1500-kg car accelerates from 0 to 2b bl t) 7tk51b8)+ma y9v8t/.kgi9gstym reln5 m/s in 7.0 s. What is the average power delivk19/)ti8 rbtlk. t8y snebag5 t y9g)+blv m7mered by the engine? (1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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