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

1#

What is the correct unit of work exp5 k na r1ec:*ip-pu7irressed 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 7 jt1on/2 jen0+0zysfj)woq ua system if there is no motion?

A. Yes, if an outside force is provided.

B. Yes, since motion is only relative.

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

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

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3#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you push twice as hard against 7 e-s :hezg/8/miusqwa stationary brick wall, the amount of work you sqe:z/use hw-8i gm 7/do

A. doubles.

B. is cut in half.

C. remains constant but non-zero.

D. remains constant at zero.

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4#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 50-N object was lifted 2.0 m vertically and is being held there. How muchnc2 oxm t2ay,5 work is being done i,2y m5 ao2tnxcn holding the box in this position?

A. more than 100 J

B. 100 J

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

D. 0 J

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5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you walk 5.0 m horizontally forward at a constant velocity6d o)g;p :+4 wtodokvx carrying a 10-N object, the amount of workwko;dop6+ x o 4tgv)d: 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 wf nv ocx93 *-r,2tojs3.0 m then returned to its original position. -,32rtv9oc*osjxwfn If the total weight is 30 N, how much work was done?

A. $45 \; J$

B. $90 \; J$

C. $180 \; J$

D. No work was done.

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7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Does the centripetal force acting on an obj;/gbitz-yl:lrc ,h,-shi /t,gc5m spect 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 whxd,zvf 2* h0xku(o,nkile the ball goes up witovhk*xkfxd,un z( ,2 0h the sign of the work done by gravity while it goes down.

A. Work is + on the way up and + on the way down.

B. Work is + on the way up and - on the way down.

C. Work is - on the way up and + on the way down.

D. Work is - on the way up and - on the way down.

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9#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The area under the curve, on a Force versus position (F vs. x) graph, repres6n 4cq+ l )qn0vwv8ytqents6+) qwy clvtv4qn8n0q

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), whatfd 7*y 6d9kd m.au2mya2rcx7f represents the work done by t7mmacdy 6. 9yakrfd*uf 2dx27he 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 kineti dg, 13+pkr*gkk 5hkhoc q-zr7c 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 nno9y f3m1l)o d4(ec73oiwzfdk v87 +wt) vdson an object is negative, then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

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14#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If the net work done on an object is zero:g9 4alb)v6ks dx5jlf, 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 mfbzbv10b+cod nf6us,p2 jv0 ,oving at twice the speed of the car. Which statement is tru0fson1b zv02bd bf+jcv,, p6ue 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 car K, andeb0ac1 qck9( +z8 svu4y lro+r car J has half the mass of car K. The kinetic energy of car J, compared to car K i(l4uykvaro+8s1 +0zec q 9crbs

A. the same.

B. 2 to 1.

C. 4 to 1.

D. 1 to 2.

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17#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object hits a wall and bounces back with half of its original spa/ 07fan4h izyeed. What is the ratio of the final kinetic eney 0/h4af7azni rgy 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 aq/ooz e * t9(8b9aqd.ge4/j hj wqohz.nd a pebble is moving at a speed of 5 m/s. If both objects have the same kinetic energy, what is the ratio of the bricb/9 o9oz8 zoeaj../g4ethdw qqq*hj (k'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 1kl .e -.aj xpvr*ezr038h qqq1.0-kg mass is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to*ra v q8-l. q1hzrekqjp.e03x 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 your car 4ob y)eq9m, q,m.yd vuin 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 q)mbq y9 e4.d,,umvoy 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 ellipticalp( d- ivpyme7. orbit. Neglecting any friction effects, what happens to the planet's kinetic eny(.mivp-7 pd eergy?

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 principle.jjz *aunbn/7qlg0zqpp p )68*

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 ug i+suengxw0df7 ;g/*;aq)+uwxr 4h 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, .x:hn)uzao: sp2ioer7g p7g ground. A second object with four times the mass of the first if released from the same height. The potent 2n:u7 s 7:g.xe) iropzpgao,hial 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 attat16u kfs2qh( nched to the end of a spring causes it to stretch 5.0 cm. If another 0.200-kg mass is added to the spring, theqsk1tf26h n(u 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 energyl2 eoo2cng)f. 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. Coa*g e+/v oq-j y5lv)vxmpare its kinetic energy K, to its potential energy l-*jvqxe)5v voy a/ g+U.

A. K increases and U decreases.

B. K decreases and U decreases.

C. K increases and U increases.

D. K decreases and U increases.

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30#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Describe the energy of a car driving up m/ +q243yyfv y3eoirma 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 arci-pf*z,8 rz,j ohcv: 4* pfi2 /cbrvje sliding with equal speeds along a level frictionless surface. They both slide up the same fricti2fb:p *ijvjc/, z-4 , * 8pzhvrrifcoconless 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 :b .;lxbg vll1$m_{1}$ and $m_{2}$ at the top of two frictionless inclined planes. Both masses start from rest at the same height. However, the plane on which $m_{1}$ sits is at an angle of $30^{\circ}$ with the horizontal, while the plane on which $m_{2}$ sits is at $60^{\circ}$. If the masses are released, which is going faster at the bottom of its plane?

A. $m_{1}$

B. $m_{2}$

C. They both are going the same speed.

D. cannot be determined without knowing the masses

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33#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the principle of conservation of mechanical energy for9-2 srwmn;sv p conservative forcesr;n2mwvs 9s- p.

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 thb;cpbq*6o8 b8 +ifgh.e)/ 3vlp mjn cce top of a building, through the air (air friction is present), to the ground below. How does the kinetic enebp )o c fqbm. *ng cbvc;/38lhe68j+iprgy (K) just before striking the ground compare to the potential energy (U) at the top of the building?

A. K is equal to U.

B. K is greater than U.

C. K is less than U.

D. It is impossible to tell.

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35#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A ball drops some distance and gainsy s8pfm+jw( o* 30 J of kinetic energy. Do not ignore air resistance. How much gravitational potential energy did the ball los* wp+(msfjoy 8e?

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 gravib 6pwcnpl o3i et9f/;6tational potential energy. Doln epwf/o6tbc 39 p;i6 not ignore 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 energk-rz75rc bfx - sn*em/t:.ki4 7vkph iy.

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;z v:v*1cjor jyth6q5

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 unisdg8)a5cx gjz: c tg4;t 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, whnwe sc c3 /zfs hgkhn)(. h*8+d36jnizich 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 w7*h69 x0mkqghlmq7 +xc-otj work in one-third the time. To do so, your power output muhqohc-+9 tgj0w6mkxx*mq7l 7st 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 w1 0cksbi -tio--yfcklr46h7at a constant 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 vertically 2.0 m and held 37gaexunyquwrbs :r :9 wu9r 6. hrux7k0z;y-there. If the object weighs 90 N, how much work was done in lirxub;y r . su73kuanx7-0:uzr6r hqe: g9y 9wwfting 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 dis)bsp9piwcwo6b 045 s ttance of 1.0 m, at a constant velocity of 0.50 ms9o6 b ip0tw)wc4 5pbs/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 constant force of 5500 N fo.u o w)g67gkct* pd**h uz*cxfr a distance of 50.0 m. What is the work done by the 5500 N for **g*ptdu)xg7cu6fwo z.khc *ce?

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 ofb*izzw+px (x a fmvpi39;: ri1 5500 N for a distance of 50.0 m. What is the work w fb(;:1mpiz9 *xp ii3raxz+vdone 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 04;h-s,sy5aw *ukzy s*ldl:g xal5tu5500 N for a distanct *: zl, 5lk-04xlg u*ds;yswhausay5e of 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 m3y i t tc4r4c+o:td;f.zq 3pzz 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 frui8g,q5 edi ;ja,/d tfumt slides 8.0 m down a ramp, inclined at $30^{\circ}$ from the horizontal. If the box slides at a constant velocity of 5.00 m/s, what is the work done by the weight of the box?

A. $157 \; J$

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

C. $78.4 \; J$

D. $-78.4 \; J$

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50#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Matthew pulls his little sister Sarahd.w5k4 e8s wmzcxhamlj,7 6.h in a sled on an icy surface (assume no friction), with a force of 60.0 N at an anglewehx m4sckm5hjd .z.l87a 6w , 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 inwjq e q45v/u70r* 0neu7eupuz the direction of the force. The graph in Fig. 6-1 shows0n uer qej7*v40/q ue7uu5zp w the force versus the object's position. Find the work done when the object moves from 0 to 2.0 m.

本题所包含的其它图片:

A. $20 \; J$

B. $40 \; J$

C. $60 \; J$

D. $80 \; J$

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52#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the direction mtvztioc05l+7 ufp x a) (/6j.jpvj- aof the force. The graph in Fig. 6-1 shows the force versus vjif6a) .jaojp0mlc-+/t 7p5 vx (ztuthe 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 force. The graph in Fixa ; wfzm+m 5azc6+ 8+emql*(pzoy a4og. 6-1 shows the force versus the object's positioma(z wymqzl+zca+fp6o* mao54;e8x+ n. 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. j-4,hj7y3akt3h*dq(s u bf puThe graph in Fig. 6-1 shows the force versus the object's position.h3f4dp,q-kyutu7(jsbja *3 h 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+go:rya-qch8 qht( -zzw7i)d to move a 55-kg cart (initially at rest) across a 10 m level surface. What is theq)hz+i8d ht zg :(rcw-y-ao q7 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 (initiallyj31:z- k wbojz at rest) across a 10 zj3o-b z1w jk: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. uljxy+ skh(e jc,d1 -hb15k-;3bkyg lHow much work is required to stopkly; sjjcg1u-3, ybh hb1+(5x dkkel- the mass?

A. $50 \; J$

B. $75 \; J$

C. $100 \; J$

D. $125 \; J$

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58#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If it takes 50 m to stop a car initially moving at 25 m/s, what -:r; uo 8 q) aly+:snswrtv2ludistance is required to stop a car moving at 50 m/s under the samesqo ls)y:u+-rl :wvu a8;r tn2 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 b(el gp/mb)9mt w wx9g5y exerting a force of 20 N over a distance of 5.0 cm g(/m9)wet xp5wglm9b. 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 horizontal component of 80 N and a vertical cqye auk bm. 54ofbk,;*omponent of 60 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2.0 m ;q*eak .kb, b4ymfo 5uhorizontally 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 oz; 2y5 bgfe:khorizontally into a bale of hay, striking the hay with a velocity of 60 m/s. It penetrates a depth of 20g;:ebkz52o f y cm before stopping. What is the average stopping force acting on the arrow?

A. $45 \; N$

B. $90 \; N$

C. $180 \; N$

D. $360 \; N$

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62#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 15.0-kg object is moved from a hepy,i +:p4bp-tq vi o8iight of 7.00 m above a floor to a height of 13.0 m above the floor. What is the change in gravitational pi-,i8tp 4p vibpy:+oqotential 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 j upkk)t:f:)q inclined plane. The plane is 4.0 m long and rises 2.0 m. If th)tqkk jufp :):e plane is frictionless, how much work was done by the push?

A. $1600 \; J$

B. $800 \; J$

C. $400 \; J$

D. $100 \; J$

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64#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-kg mass, hung onto a spring, causes the spring to stretch 2favvra.jm3 aen b-/3 ;k;gdq9.0 cm. What is the spring constant?kev ar9fv.;/g m3b d3qa;-jan

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 r j *(vl*vhgi 62igj69gitkwe-q1u2pconstant of 60 N/m. How much potential energy does it store, when stretched by 1.0 c gwti kviq*(hrle6j6 1v9p* jgg22-i um?

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

B. $0.30 \; J$

C. $60 \; J$

D. $600 \; J$

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66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Calculate the work required to compress an initiall6) dni-f 2lowyy uncompressed spring with a spring constant of 25 N/fnwi-do2 6ly)m by 10 cm.

A. $0.10 \; J$

B. $0.13 \; J$

C. $0.17 \; J$

D. $0.25 \; J$

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67#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What work is required to stretch a sprin:rigr8gwt 4x4to-6r gs q m*l97 shmlvn9ez;/ g of spring constant 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretched position 9 ;qi7:gxolw nsm/sr4vzt8gemrr 6lh9 tg4-* 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 1 ,gjcyhs7 (j;it8d fjw(id 2fmv1so7 85 N/m is initially compressed by 3.0 cm. How much work is required to compressmcs7sj 7dvj 8;y,fj1hg (o8fdwti(i 2 the 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 50-4 .(* ouprmxewm high slope. What is the speed of the skier on reac.xo4 wrm p*(euhing the bottom of the slope? (neglect friction)

A. 22 m/s

B. 31 m/s

C. 38 m/s

D. 41 m/s

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70#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A skier, of mass 40 kg, pushes off the top of a hill with an initial spegn/xptb.) jzcg f qaqezw1of; .2 .)u/ed of 4.0 m/s. Neglecting friction, how fast will she be movingp e.z/fwjt f a)qx2n)ou /;zc.q1g .gb 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 9dtdg8vrlk1nu ux2f 1 x,,di*the bottom, it has a speed of 9.80 m/s. What is the vertical heightlkni*, ,v2 rg8f d9du1u1d xxt 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 abovuk+ rvf-1 ttk2 82ou 9oa*f2g qy.svjoe the floor, its potential energo ajqgu tst2u- 82oov9ry.v*f+kk12f y 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+nd2 37cyr ac4w xrdb7 level with a kinetic energy of 40 J. At the exact top of its trajectory, its total mechanical energy is 14bc2w7+r na 37x dr4cdy0 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 grounr)23,f* vw jomq9dbp6 nt3 vevd with a kinetic energy of 220 J. At the highest point in its trajectory, its ki*jd6 wtef3r,3nvbo )9pq vm 2vnetic 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 acb /3 )ixx qgxvo/mrrnz ,23k1t a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what wv xngqr/x3x2r)m3 kb 1,ciz/oill 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 ;um 6wd 33 d3o1wiltk1tw (wbnspeed of 5.0 m/s 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 30d6imb ( w33;wwo 1wdult 13knt 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 te,k(u;+tvf3:s xt qlrs (9jvyhe bottom of a dip with a speed of 25 m/s (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, whi+fke qr9,utv3( stvjl;s :y(xch 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 itmlao lbf -p7/4s 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 lb;fybl/r);w : aj0eu pulled 0.23 m away from the vertical axis and released from rest. What will be its speeder;yb)f ljb ;0ulwa/: at the bottom of its swing?

A. 0.3144 m/s

B. 0.838 m/s

C. 1.258 m/s

D. 1.048 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 uncomp94wvt3g y yet6ressed horizontal spring with spring cons 9wvey4t3y g6ttant 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 2000 kg car to stop-3i/zx y4+pvnc+ b0yw g b5*.q alymow for a red light. Whazqwgvb*ay5cmn/x 30w p y +-o.by4li+t 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 horizontq il19u:.jbjeftuk** al surface is 50.0 N. I1 e*j ql* fj:kuu9ibt.f the initial 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, le4o5 vznjm-k3jvel surface. It has 24 J of kinetic energy. The friction force ok 34zn jo-5vjmn it is a constant 0.50 N. How far will it slide?

A. $2.0 \; m$

B. $12 \; m$

C. $24 \; m$

D. $48 \; m$

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86#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force of 10 N is applie5 k.on 7tu6uzhd horizontally to a 2.0-kg mass on a level surface. The coefficient of kinetic friction between the mass and the surface is 0.20. If the mass is moved a distance of 106khn.to uu75z 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-m high 3 lhlv-r2) fivslope. If the work done by friction ih-l v2)vlr fi3s $-6.0 \times 10^{3} \; J$, 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. The plane is 4.0 m lonz9 dmxy1tk*ni , 7 r,xbrrg6+bg and rises 2.0 m. It requires 3200 J of work to get the box bx r+y,*9mn,zrx7d g6ib1rkt 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 inclined at 20e above (;vcx t-pp+tvmf zuyg8(t-w8horizontal. The coefficient of kinetic friction between the mass and the plane is 0.20. What w8t ;p-ypvw +xugzt8ct-mvf((ill 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, an)3 se3p3*xmg, jhyxke (7v kgzd strikes the ground with a velocity of 7.00 m/s. What average force of air fri v(xy,3z )pkg3mj7*hee gsk3xction 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 6*1kyas0sti s when he runs up a flight of stairs 10.00s*k 6s taisy1-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 objec m bhg2hoa0v2ybn/0 f7t with a constant velocity of 5.0 m/s. What power m b2y2h7og0vnfm/hba 0ust be delivered to the object by the force?

A. $0.50 \; W$

B. $1.0 \; W$

C. $50 \; W$

D. $100 \; W$

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93#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

How many joules of energy are used by a 1.0 he;abp/ d)z fj2p motor that runs for 1.0 hr? (1 hp = 746 W)/a fdp2)zb;je

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 theu7yq e gcckmj: (/(cr8pc8rtji :1ct7 rate of 500 W while riding. How much force does her foot push with when she is traveling at 8.0ci8:c( u/ cjm7tqtcj1 yrk(gc:erp87 m/s?

A. $31 \; N$

B. $63 \; N$

C. $80 \; N$

D. $4000 \; N$

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95#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1500-kg car accelerates from 0 to 25 m/s in 7.0 s. Wha jh :7muznj fti)q1 t4a0z:ds3t is the average power delivered by the engine? (1 hp = 7467ht:j dq:uit3 4nj zfmzs0)a 1 W)

A. $60 \; hp$

B. $70 \; hp$

C. $80 \; hp$

D. $90 \; hp$

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