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

1#

What is the correct unit of+k5ivl. pous v;n-vudn5l 3c8 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 system if there is no m3fvlvn;i7 :zf otion?

A. Yes, if an outside force is provided.

B. Yes, since motion is only relative.

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

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

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3#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you push twice as hard against a stationary brick wall, thgne0bp)b*:ii,1nwv ee amount of work you doenbi ,e*:1b0)i vpg wn

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)6iyzvn:e mgs(f2 w)l 2.0 m vertically and is being held there. How much work is being done in holding the box in ms e2 wivl6( :yzng))fthis position?

A. more than 100 J

B. 100 J

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

D. 0 J

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5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you walk 5.0 m horizontally forward at a constant velocity carrying a 10-N osx8o9 ,ti5mb-g xeys )bject, the amount of work you do i xseb9tx s5)y8ogi-,m s

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 returned i4i*bivf- v 1*p-c)y c4epvsoto its original position. If the total weight is 30 y4*v c-ii1e)vivfop* 4bspc - 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 object do work on the object?ei ruad xag63m+y bf80l*c1 k)

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 gaf-c d4md-e6j ravity while the ball goes up with the sign of the work done by gravity while it gjd-cdf6 - 4emaoes 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, repfs-,qzqa7j 9zresentsz7q 9sfjaz,-q

A. work.

B. kinetic energy.

C. power.

D. potential energy.

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10#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

On a plot of Force versus position (F vs. x), what represents the wopc qga34f wous2::p)m rk done by t:a fgs 23qw:oum)p4pche force F?

A. the slope of the curve

B. the length of the curve

C. the area under the curve

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

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11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

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

A. the kinetic energy of the object.

B. the potential energy of the object.

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

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

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12#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is positive, then the object's:m jusdd dlf ( tzdr0b.u(70n6chw x/6 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 objec dh:.thj 9h9qtoem/3t t'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 objelum*my nh2,ib(+xp/zci7 p;rct 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,x*r8w,3k/o tf(ep ny d and is moving at twice the speed of the car. Which statement is true about the truck's kinetic energy cof xk(y*8 3pdwo/ ,rtnempared 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 half 7x+oo wn ypq23the mass of car K. The kinetic energy of car J, compared toqypn7 ow+ 3ox2 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 wallcd04,asz l x.*8egfhvhr40 bw and bounces back with half of its original speed. What is the ratio of the final kinetic energy fawz ,lb.cghv0*de8rh 44sx0 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 of5z(yn9zw,z gk t9q7 l*tjy -sxegog3v) w8(ry 3 m/s and a pebble is moving at a speed of 5 m/s. If both objezwk wytl)g37 vyg *qngs5-o( e9(98,zz xj tyrcts 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 m9tnq r8vr9yadj2h/swe650 45wv c cqz/s. A 1.0-kg mass is moving with speed 4.0 m/s. 6 4 cjashezvqw58v q20crrn5wy /t9d9Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?

A. the 4.0-kg mass

B. the 1.0-kg mass

C. Both travel the same distance.

D. cannot be determined from the information given

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20#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You slam on the brakes of igowd9*/ b-r iyour car in a panic, and skid a certain distance on a straight, level road. If you had beeob9i -*i/gdrwn traveling twice as fast, what distance would the car have skidded, under the same conditions?

A. It would have skidded 4 times farther.

B. It would have skidded twice as far.

C. It would have skidded 1.4 times farther.

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

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A planet of constant mass orbits the Sun in an elliptical orbit. Neglecting anyp*j ik kqx w1)x.t/c:z f )ixxk pk /*czqt.j:1wriction effects, what happens to the planet's kinetic energy?

A. It remains constant.

B. It increases continually.

C. It decreases continually.

D. It increases when the planet approaches the Sun, and decreases when it moves farther away.

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22#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the work-energy principlkfb4)o)otu /7inc.4x0(f q5 upr. rew1b gdxme.

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 3vb0:toc kw+ shave 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 hei2nug- )a0 rskight h above the ground. A second object with four times the mass of the first if released from the same height. The potential energyrun s2)i-0kga 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 adg4 kiit-+7kmw rhh:b,-kq1 5.0 cm. If another 0.200-kg mass is added to the spring, the potential energy of the spring ktr1w -7,+k-:bdm qa4hk igi hwill be

A. the same.

B. twice as much.

C. 3 times as much.

D. 4 times as much.

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28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The total mechanical energy of a sys+5d 1jl5kb0amlc8jv ltem

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. c3 p;l; 6x)z4a-evi f4a7gj:iylxb(1zothmd Compare its kinetic energy K, to its potential energz1;6vf zi3 dyx tlga;pcoa e7b-h44m)j x :l(iy 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 driv9+ew) twu9 pna 2q ogb)y24cuiing up a hill.

A. entirely kinetic

B. entirely potential

C. both kinetic and potential

D. gravitational

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31#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A lightweight object and a very heavy object are sliding with equal svo+,y(9s s//f ) m(enw wcvvurpeeds along a level frictionless surface. They botcv9 r vvsyuwm)//s (wo+(e,f nh 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 qr 98)vrf /my6y4ylwt $m_{1}$ 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 f+ l+d*zpi -xs3/vpsc mechanical energy for conservative forcesl fs3x*pc /+z sdpv+i-.

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:;7 nlv6 odwky of a building, through the air (air friction is present), to the ground below. How does the kinetic energy (K) just before striking the grol;w 6:o7y dkvnund 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 energyxfp(8 gbvjz 4,. Do not ignore air resistance. How much gravitational potential energy did the ball lgzf v4jpb8( ,xose?

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 aj2 9a.k wi* 4kvyw1ny:qwp+oa3wpl x;nd loses 30 J of gravitational potential energy. Do not ignore air resistance. .k3lny4 1;:aap 9ow2jwiv*+kqpy w xw 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 1 lbna, htmufg s7eag4 .c*-:xgc7b3uenergy.

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 )+yny( .c/)zy fwaaea

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 powern/r-l-p t,oof 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-s e )e- j39p,ojcj5bnqwyt+h 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 .dmh4:wqouh 6iq.us.kcm;p8 i ad6 jk n2n1k0time. To do so, your power output must hakh6. h8m qkwqu:jn41 m dna iu2k.opd ;isc.06ve 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 const98ajc djxccih2r 1*oh ,gh fb757d(bv8 3ihprant acceleration, 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 verticalld+mc1/5hmqmq0i yqh7 aky 5h1y 2.0 m and held there. If the object weighs 90 N, how muchq/chdyq5m5hhqy+a mm171ik0 work was done in lifting it?

A. $360 \; J$

B. $180 \; J$

C. $90 \; J$

D. $0 \; J$

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44#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You lift a 10-N physics book up in the air a distanc4); n5qbxvlxz e of 1.0 m, at a constant velocity of 0.vnx lbq;)4xz550 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 e . m+ n7yvgp3m5.n tm4dfg/mzwith a constant force of 5500 N for a distance of 50.0 m. What isgmm nte.5z3mgfn7 m/pv. +y d4 the 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 for . wn4uw)u, ocm:aecp:a distance of 50.0 me) omnc:uwwc,.p: au 4. 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 a constant force of 5500 N fobtl3mmvqf 0js:k+ s 41r a distance vlf13t sbmsm:qk 4+0jof 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 6.0 m up a 8unw.jac-b *slong a $37^{\circ}$ inclined plane. What is the work done by the weight (gravitational force) of the box?

A. $-11 \; J$

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

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

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

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49#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.00-kg box of fruit slides 8.0 m down a ramp, inclined 2h qlad2g7l ik)wp7q.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 (assum 8erh+(suv ae;e no friction), withae+r us8h;v( e a force of 60.0 N at an angle of $37^{\circ}$ upward from the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew?

A. $185 \; J$

B. $433 \; J$

C. $575 \; J$

D. $720 \; J$

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51#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction of the force. The graphw3ql*amiy ll k.uo/ s1hx ).0x in Fig. 6-1 shows the force versus the ok/uql)xs1l0o 3wily. h.*ma xbject'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 the0sae i )k,jva+ direction of the force. The graph in Fig. 6-1 shows the force versaevi+0,a sk)jus 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 fg y7aqz-h g9m ),ojnecp ;08nzorce. The graph in Fig. 6-1 shows the force versus the object's posim;a ,n ozn)q-e07 gyghz98pcjtion. 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 graph in Figc wkg)k bcgh/ep/8 +i-. 6-1 shows the force versus the object's position. Find the wb kkip+ cgch)/8 -gwe/ork 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 ca n enzg0+k ;1;xn*op(drapxf 3rt (initially at rest) across a 10 m level surface. What 0 parxz*x;efn+3;g(okn1p dn 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 Nj q v: sx1ivah0:lk1:rdv w0wh9jgp/s5z 9 .cw is applied to move a 55-kg cart (initially at rest) acrja1j5d/r:isv 9 h0c q p vlgx.:zsk0w:1 hvw9woss 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 much work is requirdb ks;2*9g;bfzk0 idhed to stop the massdi9h 2gkzk s; 0*dbb;f?

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 stv f fjh zx(6q5,8o;g1,v cpqvbop a car initially moving at 25 m/s, what distance is required to stop a car moving a vgpf6, 5xvoj,b q(h;z f18vcqt 50 m/s under the same condition?

A. $50 \; m$

B. $100 \; m$

C. $200 \; m$

D. $400 \; m$

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59#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring-driven dart gun propels a 10-g dart. It is cocked by exertigwcqngnuz.e)g1-t g *o :/6 vqng a force of 20 N over)*gn ueng g-qt16o .gqw cvz:/ a distance of 5.0 cm. With what speed 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 hja0 z,g.a( e8vf./aahauk 9lporizontal component of 80 N and a vertical component of 60 N. The force is applied to a box which resta(favj ek uzg0aaa9/.8lh p,.s on a level frictionless floor. The cart starts from rest, and moves 2.0 m horizontally along the floor. What is the cart's final kinetic energy?

A. $200 \; J$

B. $160 \; J$

C. $120 \; J$

D. zero

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61#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An arrow of mass 20 g is shot ho2uecs4bkarn) w3/ha( df4d0krizontally into 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 acting onfk 3ddw2(a44rhken0b u)/ cas 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 hns7;wdk lb. dot;6yy; 8,uvvfrom a height of 7.00 m above a floor to a height of 13.0 m above the floor. What is the change in gravitato6lh;7.dsk,8n ;y;ubd vy wtv ional potential energy?

A. zero

B. 1030 J

C. 1176 J

D. 1910 J

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63#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 400-N box is pushed up an inclined plane. The plane is 4.0 m hoe *: 7,my r0fhpn9qolong and rises 2.0 m. If the plane is frictionless, how much work was done 0oe 9h:fo7,r*mhy n qpby 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 stretch 2; hjsihz2g0*+:uc+bsg/amr i.0 cm. What is the spring consg+ig:bh; s*02c ai/s+muhzr jtant?

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. Hol6v5xigio)+ d w much potential energy does it storelv)5+g 6oi xid, 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 requirep/ tjd u,/6; +twjdwlad to compress an initially uncompressed spring with a spring constaj,+l/u/6 dpdwjt tw ;ant 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 ( eni, p*xr8fba spring of spring constant 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretcheb(i px*enr,8f d position is at x = 0.)

A. $0.45 \; J$

B. $0.80 \; J$

C. $1.3 \; J$

D. $0.050 \; J$

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68#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring with a spring constant of 15 N/m is initially compressed by 3.aumi( -85vnk/ gyg- ju0 cm. How much work is required to compress the s8a gyu -5j-igm /vunk(pring 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 higf92j8pekqf n (g2ln58if8 foy h slope. What is the speed of the skier on reaching the bnoif 2l8n8f8 kfqg 5(fj29pyeottom of the slope? (neglect friction)

A. 22 m/s

B. 31 m/s

C. 38 m/s

D. 41 m/s

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70#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A skier, of mass 40 kg, pushes off the top of a hill with an va a*as32/ sdairp8movh* s:9 initial speed of 4.0 m/s. Neglecting friction, how fast will she m9h aa* i3sdar/8ov:v *a2s psbe 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 ,k90kcf e /eyco7g gls43:ld splane. At the bottom, it has a speed of 9.80 m/s. What is the vertical he s0/gl4yl fo:, eg937 kckdcesight 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 the floor8g a w -2innpgi em306k-cj*kf, its potentij6m n-0e kip-w83*gfkc in2agal energy exactly equals its kinetic energy. How fast is it moving?

A. 3.7 m/s

B. 6.9 m/s

C. 14 m/s

D. 45 m/s

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73#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A toy rocket, weighing 10 N, blasts straight up from ground leh1c,(rknji( o g2 )cdjvel with a kinetic energy of 40 J. At the exact top of its trajectory, its total mechanical energy is 140 J. ,r jhc( )n j2kgdoci1(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 g/x7b+rv y 33xzzce1jmround with a kinetic energy of 220 J. At the highest point in its trajectory, its kinetic energy is 120 J. To what vertical height, rzx 7y v xr3j1/cm3eb+zelative 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 star8/xgqxnh + sygfd 8 5f9*say6xts from rest 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, which is 30 ssn95+ fx fy8* xq/x 8ahggd6ym 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 rrekp0 -c(q 1opoint 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what wo0e1qcpr -( rkill 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 the bottom of a dip with a speed0ip)6 6jnu h4dh 1gkwwdm,u:b of 25 m/s (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 45 m above the bottomph66n h g4dki:wbm)u0 jw1ud, 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 bal ps5 .(reid:m9*mlt2)rtsxf ll at the bottom of its swing (point

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79#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A:2.2 m/s

A. 3.1 m/s

B. 4.4 m/s

C. 4.9 m/s

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80#

( 1.0 分) 切至整卷模式搜藏此题

难度:2

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81#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2-kg pendulum of length 50 cm is pulled 0.20*c z*zzcd*89, ohs5nira j4zqob.qm. m away from the vertical axis and released fro,5zc4qjz 8a.z9s*crono*bdmzh *i.q m rest. What will be its speed at the bottom of its swing?

A. 0.2714 m/s

B. 0.724 m/s

C. 1.085 m/s

D. 0.905 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 horizont(*m0nmuqj npl4/qg. wair6 qn m+g9*+/eum smal spring wi6j9. q/q 0mum w*mma 4+/(nr+s qe*nggui mlnpth spring constant 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/r42vn ;h(l v t,tmb-vcs, slows down her 2000 kg car to stop for a red light. Wtvhl m(2cntv;, v4-r bhat 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 objecte:8ayqt h,i+y and a horizontal surface is 50.0 N. If the initial speed of th+8h:q,ey ytia e 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 roucunr*4xpy 7 :vgh, level surface. It has 24 J of kinetic energy. The friction force on it is a constant 0.50 N. How far wv7y4:cun * xrpill 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 .): rpreu g1u-3wimpu a level surface. The coefficient of kinetic friction between the mass and the sur)r .p-uwiueurp:m1g3face 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-m4/ ;l*e8fvakk3 fk osu high slope. If the work done by friction; s 8oavf*ef/k34lu kk is $-6.0 \times 10^{3} \; J$, what is the speed of the skier on reaching the bottom of the slope?

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88#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An 800-N box is pushed up an inclined plane. w eal0r4;zjkfhq.t -2 The plane is 4.0 m long and rises 2.0 m. Ithaw2eqf-0.jk4;r zl t requires 3200 J of work to get the box to the top of the plane. What was the magnitude of the average friction force on 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 inclina1lgo9d, pqaw:c d5i:ed at 20e above horizontal. The coefficient of kinetic friction between the mass and the plane is pwc al9 ,aqo:dg5 i:d10.20. 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 he, f fvm)g8n5t tym+66p:l ayttight of 10.0 m, and strikes the ground with a velocity of 7.00 m/s. Wh+tm6g:ln,yvyt5tat pm8 ff)6 at 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 enercp1fl0v 4gnwdd)5 bhm a 0.3wdgy when he runs up a flight of stairs 10.0-mbalv04 md3cd0g.)1w f whp 5dn 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 10 j6pw,:uamb cq5 of-y6znaj to move an object with a constant velocity of 5.0 m/s. What power must be den 6w :bam 0uyf6j zpqoja15-,clivered to the object by the force?

A. $0.50 \; W$

B. $1.0 \; W$

C. $50 \; W$

D. $100 \; W$

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93#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

How many joules of energy are used by a 1.0 hp motor that rundakg7 5hi3 ,n9j dz/mrs for 1.0 hr? (1 hp =i zj 9/57r akdnmh,gd3 746 W)

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

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

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

D. $4.8 \; J$

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94#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A cyclist does work at the rate of 500 W while riding. How dp427u uev,mw much force does her fop vm7u24,u ewdot push 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 25 m/s ip u 2 ph1jl/gl:):td lzkp:k.in 7.0 s. What is the average power delivered by the engine? (1 hp = 7z .dikgppktll :l ::)/pj2 u1h46 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87	88	89	90
91	92	93	94	95

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87	88	89	90
91	92	93	94	95