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

1#

What is the correct unit va- p0bpa q agnt.1g4: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 sy7c ;6t guzkv/istem 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 stationaryg6 -xqhrul 8k):33hb ljyi 8df brick wall, the amount of work you f8u ) bxhyqr:638idkg llj3h- 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 hr vw0x(zbq4, o+ -gejheld there. How much work is being done in holding the box in this pox04,r-hgb(q w vezjo+sition?

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 horitupd xm,mmw, -v7:wmf 5f(8fe zontally forward at a constant velocity carrying a 10-N object, theu8fte xwf-: pfmm,m(5v 7dw,m 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 then lqk q6g( e 8z3ompb,l2q.rih* returned to its original position. If the total weight is 30 N, how much work 8, gblr3qk.hzlqmpe qo*6i(2 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 object do worklw u*9b llny6e9;r*k x 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 sig,h7yl xg2of8o ad-k r1n of the work done by gravity while the ball goes up with the sign of the work do -ld2gk, 71oayhf ox8rne 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)g1,c gg)twqe; a+u7nv graph, represents +gw ntv7 )1gue;c,qga

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 versu/ )wd4(vi xrmk3la26medajn(69s yzes position (F vs. x), what represents the work done by the forevx6/ik6l23 za d( ymn ewsd4(j9r am)ce 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, thenmxyi7flj8; 6e the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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13#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is negative, then the object's kinetic eneexdr/zy8 e/d( rgy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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14#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is zero, then the object's kinetic enej:n5d-ny 5viy rgy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A truck weighs twice as me k+6.jxp cg5ruch as a car, and is moving at twice the speed of the car. Which statement is tr6c xg+rpje k5.ue about 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 cax51 xv1l :u;9zu-tk4iw kta8q v hf2tjr K, and car J has half the mass of car K. The kinetic ef t;l825a t tw1-1x xk:4v9zkhuju qivnergy 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 of itu 9t.lk/6wxjps original speed. What is the ratio of the final kinettwj/9lu6 xpk.ic 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 moving at a spee lc/g9flxdd.da b1 6uowt/s,.d of 5 m/s. If both o dlgx .6dsub 1t.adloc/f9w,/ bjects 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. A 1.0-kg mass is movin,b /eety d+rk(g with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which objeckb ,e rd+(te/yt 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 yoah6iln30 xxq ;ur car in a panic, and skid a certain distance on a straight, level road. If you had been traveling twice as fast, what distance would the car hav0xinalh;q6 x3e 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 tarf8bzf*9m n +he Sun in an elliptical orbit. Neglecting any friction effects, what *8+fb9znra mfhappens 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-energy8or dv0fptnbsi9+1dyvd( :q jm 3.(u d principle.

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 potential h spey5bvyi8- c2bu1twi) )9 wenergy?

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 gn6)c m tg ur.pn)2.aqlround. A second object with four times the mass onm l upq)2 gt.ac)nr6.f the first if released from the same height. The potential energy of the second object compared to the first is

A. one-fourth as much.

B. one-half as much.

C. twice as much.

D. four times as much.

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27#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 0.200-kg mass attached to the end cr6(qo0t1x .el3 +acawpor 7 pof a spring causes it to stretch 5.0 cm. If another 0.200-kg mass is addqtp03wr e76oc.+coar xlpa (1ed 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 ejg*q. 2(elb; (entyd ynergy 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 its41dgshe/-edug /l*9qij w/sy)z3tu u kinetic energy K, to its potential energyg dgesh 9iuj*/1/s3z/- )edt 4uwlq uy 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 mt ei 2 rdwn+ -.,ulen9r9au*bof 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 heavy0;lt nnsk:xazi/*fx0 object are sliding with equal speeds along a level frictionless surface. They both slide up the xznatx 0*l:ni0; fks/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 b1xitpu,3d 0n $m_{1}$ 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 c-v2zle .t nh;5ko-kqr onservation of mechanical energy for conservative forcesnrk -2. eztqvk-l5;ho .

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 (aijod6 z+p hm*0qr friction is present), to the ground below. How does the kinetic energy (Kh+ *zpj6m d0oq) 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. Do not ignoxupm-fa 2fk9yev*i l6e: yl4:re air resistance. Howy:epk*-vl6ax92le:f4my ifu 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 and loses 30 J of gravitational potential ener) qp)j*hb ;9 2heuo q22:rrfuzuutxu1 gy. Do not ign); t1bfux2ph q*2eouru :uu )zqh9rj 2ore air resistance. 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 of energwne55gdqx0:j 0ieom c) e0dg0y.

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 isr4i i8wcvc +l3f4sd(f

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 unf*z415yk wgva it of power expressed in SI units?

A. $kg m/s^2$

B. $kg m^{2}/s^2$

C. $kg m^{2}/s^3$

D. $kg^2 m/s^2$

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40#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Of the following, which is not a unit of power?9 b +v5(ggc:et8y u,wocsw8zl, co ,/pjh oi6v

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 tpni-m :2r0k oahe time. To do so, your power output mus-pn m: kaoir02t 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,5hmjo8iui : /9ng y*lw 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 veswixylop *zg3*jp6c ,j56 ; zurtically 2.0 m and held there. If the object weighs 90 N, how much work was dsgl j*xzpwcpo5 i,yz6 ;ju6*3one 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 1.06,rsvnhp*bna8 eh w1xr-7/r oxyah;/ m, at a constant velocity of 0.50 m/s. What is the work done by tha6-o,8ph e;n*hxn7 /sawyvh1 rx b/rr e 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 pulle;;dii x,z jaf*d upward with a constant force of 5500 N for a distance of 50.0 m. What is th ;a;xdjf z*ii,e work done by the 5500 N force?

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

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

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

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

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46#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 500-kg elevator is pulled upward with a constant force of 5500 N fos r61w;r+l.9vxnjtm y r a distance of 50.0 m.r6n mvslrj9 y 1t.x;+w What is 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 pulled upward with:kgvdtqsq 6 v82m.h: j a constant force of 5500 N for a distance o .t8 hvj:s2q:mdg 6vkqf 50.0 m. 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 gh-sk(kur :m9my(ru 76.0 m 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 slides 8.0 m down a8 ombu6 d*6gupu*axs 8 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 sleva( nak7k,wnkuml690g2vi zq/d f8.:n r)dp ad on an icy surface (assume no friction), with a ffv,v69zn )lu dqg(/r iaakdwan mn:.7 802kpkorce of 60.0 N at an angle of $37^{\circ}$ upward from the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew?

A. $185 \; J$

B. $433 \; J$

C. $575 \; J$

D. $720 \; J$

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51#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the force.dkgn 7 z:iu*xz) /r+ax The graph in Fig. 6-1 shows the force versus thxgz / azr7x*dn+i:k)u e 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 ;nc5+aobcjek29 d lzuyv8l4. direction of the force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves from 2.5lucvolnd z2 kya8b+9j ec;.40 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 th7 ;jb h8bros-pe force. The graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object moves fr; ob7p-s br8hjom 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. ,g5xs2 nt3f waThe graph in Fig. 6-1 shows the force versus the object's position. Find the work done when the object mo 2g5f ,twxs3naves 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 (f,bvl 1aur8q (bne mx;1a zea o;9b9eis applied to move a 55-kg cart (initially at rest) across a 10 m level surface. n9 e(8mu v9 ;e;(bx,bzfoqa 1aral1beWhat 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-kg cart (init 7 lklf;:sf3e;dztv1 tially at rest) across a 10 m level surface. What is tf;:l3v ;l1etszft kd 7he 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 s(ipd80ekbl6 2tptb ; 5.0 m/s. How much work is required to stop the 6;l b2kbdept8 0ps(i tmass?

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 qbggzx3 8c-6 binitially moving at 25 m/s, what distance is required to stop a car moving at 50 m/s under the same conditioqc g 6x3bbz8g-n?

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 propel9x5 4*fozhne 4qn4)mk yarhs2 mn -dw+s a 10-g dart. It is cocked by exerting a force of 20 N over a distance of 5.0 cm. With what speewf-h*29z)ksn yn do4 m ahn54xq+e m4rd will the dart leave the gun, assuming the spring has negligible mass?

A. 10 m/s

B. 14 m/s

C. 17 m/s

D. 20 m/s

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60#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 100-N force has a horizontal component of 80 N and abo o9 fsfef7gh67f rnj-k7f6, vertical component of 60 N. The force is applied to a box which rests on a level frictionless 7j,6h n-ko gff6f9rfobs7ef 7floor. 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 a0 ,kkmzo *yezr)31whd4.nkointo 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 stopping force actingozk1ekz3dma.h0,4k onyr) *w 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 m above a floor to a height ofkh2 kvp:ieo3 r41o5x2-yzkrr 13.0 m above the floor. What is the change in gravitational potential x io o2vk4:pze y-213rrkkrh5 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 pl (a-k 3c,o;o z v7h+usincyzrc(.das -ane. The plane is 4.0 m long and rises 2.0 m. If the plane is frictionless, how much work was done by th k d aiz,oco;-sz(3y.c- rc+hvn( sau7e 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 sprkhp9gp(a,: 0edwbu-4 fo(xe j ing, causes the spring to stretch 2.0 cm. What is the spring pe ,kgd(4x(0e:h-op9 f jbuwaconstant?

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 much potentirg oo6gy5.lf/s z cno1 esyv/u93h +:fal energy does it store, when stretc/+1yyo: o cgl/ s 5h zr.6fenof9sug3vhed 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 comq9;fmsjfy: 4g g +d+gwpress an initially uncompressed spring with a spring constant of 25 N/ q;g+4w+yggsmffd : j9m 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 w0n:j 06 rlt5kxexcuhm+d(f *spring of spring constant 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretched position e rtj6cfx5 mld h*xn0+0k (wu: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 bd ez7k j2kj z*)8wd )*a7obnlN/m is initially compressed by 3.0 cm. How much work is required to compress ez72d bl) jnd*k8 o aw)jkbz*7the 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. What is the f1pafbi g69 *rsper a*if p6gf1b9ed 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, pushes off the top of a hill with an initial speedv 7u( nz qka/we4a r5*d/v.vdi of 4.0 m/s. Neglecting f *ve(5auwnzdvk 4/v/rq .7aidriction, 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 frictionless inclined plane. At the bottom, it has a sywajvd7-.udg:l6c g: a o)ox-peed of 9.80 m/:-o. cddl:uw ojy)v g7g-x6aa 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. When it is 0.70 m above tfuots3t 86k5,uvvvz 8he floor, its potential energy exactly equals 6 vut83vsut, vfo5 zk8its 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 stra5eip6 v9 vrvb)ight up from ground level with a kinetic energy of 40 J. At the exact top of its v6v 9v r5bi)eptrajectory, 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 l fqb f zy;c4okf.0aftr17+ng8 eaves the ground with a kinetic energy of 220 J. At the af oqny.+ 0g;f14k7 cfzrtbf8 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 rest at a point 45 m above the b)9 n18rp(kfhi:mldsx42o vgiottom 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 abx1r(8mlf 4v 9:gin ik2 h)sdpoove 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 bott:hr siu5sb +8tom of a dip (See Fig. 6-2). Neglect friction, whatsr: hi ub+58st will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?

本题所包含的其它图片:

A. 12 m/s

B. 14 m/s

C. 16 m/s

D. 18 m/s

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77#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster starts at a point 30 m above theeo8 *bu hmc:wv 73i)se bottom of a dip with a speed of 25 m/s (See Fig. 6-2). Neglect friction, what will be the speed of theob *mve7s u:3i )8ehwc roller coaster at the top of the next slope, which is 45 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 16 m/s

C. 18 m/s

D. 20 m/s

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78#

( 1.0 分) 切至整卷模式搜藏此题

What is the minimum speed of the ball at the bottom of its swimm+4 w:;a fv /*tdbh 5h4trvmrng (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 from the vertical ax4-- r/bgt e-baqm5m xsis and released from rest. What will qma bb4gmx t-/5r-es-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 initi1 1epc xlbyp 4ohy*8/dally uncompressed horizontal spring with spring constant of php 1 c/xb8*do ye1y4l$2.0 \times 10^6 \; N/m$. 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 200bg2ybojt-cb.0d cnu5q.0 i u00 kg car to stop for a red light. Wh nq0c-bu bd0cg..0b2 t ujo5yiat work 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 n 3zzh ;/odo*ex)wrv.gqq83 lhorizontal surface is 50.0 N. If the iw gov;3 n/)r*xed8ohqlq3zz.nitial 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 Jw.(ek9 zx;jp-vp g clcb. *qn7 of kinetic energy. The friction force on it is a ckpje7p zv9(qcn .gl* .;xwb-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 horizontall; s/qna h+o/vay to a 2.0-kg mass on a level surface. The oa +s aqnh//;vcoefficient of kinetic friction between the mass and the surface is 0.20. If the mass is moved a distance of 10 m, what is the change 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 thjt97 d(0ym6 omyp2 a;s.upj vte top of a 50-m high slope. If the work done b(t vpy6. upjyj20t;o 79m amsdy 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 osrbp4*errsl 73km4g o*j24 cinclined plane. The plane is 4.0 m long and rises 2.0 m. It requires 3200 o4k3 m 4ejgopls cr742rb**rsJ of work to get the box to the top of the plane. What was the magnitude of the average friction force on the box?

A. $0 \; N$

B. non-zero, but less than 400 N

C. $400 \; N$

D. greater than 400 N

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89#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2.0-kg mass is released from rest at the t00bc8 ) c4qu9 zjadmejop of a plane inclined at 20e above horizontal. The coefficient of kinetic friction between the mass and the plane0 8jaz4m0quej cc9) bd is 0.20. What will be the speed of the mass after sliding 4.0 m along the plane?

A. 2.2 m/s

B. 3.0 m/s

C. 3.5 m/s

D. 5.2 m/s

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90#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 30.0-N stone is dropped from a height of 10.0 m, and strikes the ground with ac9gpe,rk2 . mt velocity of 7.00 m/s. What average force of g m,2tkerc 9.pair 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 bomnzqh p/*:r 3q)jkmmg2r+ya.y using energy when he runs up a flight of stairs 10k2n a.phr*/ :qmrqm jz)y3 gm+.0-m high, in
8.00 s?

A. $75.0 \; W$

B. $735 \; W$

C. $4.80 \; kW$

D. $48 \; W$

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92#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-N force is needed to move an object with a constant velocit77w0 nuo um-z) vsi;smy of 5.0 m/s. What power must be delivered to the object by the fos 0n77v; )u swu-mimzorce?

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 1.0 hp motor that runspihhoifjj:r1u,s ,41:fj,mum6 i qt; for 1.0 hr? (1 hp = fu sji1tpoir4mh f,:: j,1 ,6miuhj; q746 W)

A. $3.6 \times 10^{3} \; J$

B. $2.7 \times 10^{6} \; J$

C. $4.5 \times 10^{4} \; J$

D. $4.8 \; J$

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94#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A cyclist does work at the rate of 500 W while riding. How mdj kd5(nbe:+ oc0jx u.nrb2*y uch force does her foot push x*nj rc(+ :20kb oe 5dd.jbnuywith 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 tos 8uqwp/v+xn- 25 m/s in 7.0 s. What is the average power delive8u/pnvxw+ qs-red by the engine? (1 hp = 746 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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