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

1#

What is the correct unit of work expressed in SI unitsqpp nfw61o0m ,awu ege)mw6q mfw2,2. ?

A.

k g m / s^{2}

B.

k g m^{2} / s

C.

k g m^{2} / s^{2}

D.

k g^{2} m / s^{2}

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 motion? i )rf:b m9*sgk5nrb7x/9tps x

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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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, ty avps*kbd0 -*m;ewc 4-c n.xqhe amount of work you -cmx-p;*yk. saeq0dbvcw4n * do

A. doubles.

B. is cut in half.

C. remains constant but non-zero.

D. remains constant at zero.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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. 5( qyj6z b(slrHow much work is being d(6r l(qsjb y5zone in holding the box in this position?

A. more than 100 J

B. 100 J

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

D. 0 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you walk 5.0 m horizontally for,knh;i )m5j;;j we lymward at a constant velocity carrying a 10-N object, the amount of work,jm)h; wj;;5ln ieykm 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 mf:yrc(f1h own f4..o9 x( h7adn(parm then returned to its original position. If the total weig: nh(hr o.yrf 91(.nffpamacw7o4x(dht is 30 N, how much work was done?

A.

45 J

B.

90 J

C.

180 J

D. No work was done.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Does the centripetal force,qz s9 z 6qe548h/. gyazbzwci* m4hmt acting on an object do work on the object?

A. Yes, since a force acts and the object moves, and work is force times distance.

B. Yes, since it takes energy to turn an object.

C. No, because the object has constant speed.

D. No, because the force and the displacement of the object are perpendicular.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 grqf /s;f //7uxhk6fudud( y/ckavity while the ball goes up with the sign of the work done by grxykf 6u/uf qc hsf;u(d/ //dk7avity 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

9#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The area under the curev,unz3yc:n-)2zj25 fs nmc ydhi 9 6ive, on a Force versus position (F vs. x) graph, representsn , -nny62cui)vzzj ic:95s32fhm dy e

A. work.

B. kinetic energy.

C. power.

D. potential energy.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 wd7+mxb a: dk5u -3bw kytb;-dfork done by thxfdk d:+3ubdy b-k7 mwa-;5bte 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity

\frac{1}{2} m v^{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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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, th5.xu w.s bc+ojen the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 obb:2yu ; vz (vh5zfa- f ugjvi)g)(v0-b+amaqr ject's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 im7-l ko q-so7*7uwhz0 l7 wrbas zero, then the object's kinetic energy

A. decreases.

B. remains the same.

C. increases.

D. is zero.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A truck weighs twice as much as pdkto)l/ .+s x 4oic/pa car, and is moving at twice the speed of the car. Which statement is true about k+sopct op.d )l/ 4xi/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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Car J moves twice as fast as cap4: *v1hd l(w3z; dma euinm1qr K, and car J has half the mass of car K. The kinetic eq;*h w4zmd11lnpeu3dv(:mai nergy of car J, compared to car K is

A. the same.

B. 2 to 1.

C. 4 to 1.

D. 1 to 2.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 originau.y/4ipzu+ps 4rkw;:sa m)ax l speed. What is the ratio of t/zpir.pwus+xu4:; ka msy 4)ahe final kinetic energy to the initial kinetic energy?

A. \frac{1}{2} \;

B. 1/4

C. 2

D. 4

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 mo ulgv;mo 8u .-3qzkhw/ving at a speed of 5 m/s. If both objects have the same kin 3qmvgul-okhuz/. ; 8wetic 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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.qaj8d :n;kyqr q2s d4:ner :e mass is moving with speed 4.0 m/snq yq ;8d2rkasjre :.q4e:n:d. Both 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

20#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You slam on the brakebq5bxa9ij5 x,s of your car in a panic, and skid a certain distance on a straight, level road. If you haxa,59j ib bqx5d been 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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. Negl)0k-sm:4m 1x slcxkmdecting any fris mk)dc0s:1k-mx l4mx ction 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

22#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the work-energy principltqj3wwf: wmgg7 l gg9v/2))*rn drv;se.

该题自我估分: (必填) (满分:1.0分)

绑定到本题的附件链接:
绑定到本题的上传图片: (问答题类型题目图片/附件必须插入上方文本框，否则会被移除题目绑定)

参考答案:

进入本题讨论区，参与讨论

标记此题

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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

24#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity

\frac{1}{2} k x^{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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

25#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Is it possible for a system to haveexa2 7 jqab lam*+:0xt 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

26#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object is released from rest a height h above the ground. A sem 1 eradv* 7k-i)qm1ppl)yjp1 cond object with four times the mass of the first if released from the same height. The potential energy of the second object ay)ej -v1dkqlpim1p p r1m7)*compared to the first is

A. one-fourth as much.

B. one-half as much.

C. twice as much.

D. four times as much.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 t4q5zigba1;rwn*2 x4 .t 2qajfjp* svso stretch 5.0 cm. If another 0.200-kg mass is added to tr4w.42 sb 2;jnzxaap 5*gi1 vfqqjst *he 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The total mechanical e+a: j us sv;u5gp /y q+akd+kxeg4z;s,nergy 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

29#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An acorn falls from a tree. Compare i3 rikuj d,h/x7 h5*qcbirv4v09*zyd its kinetic energy K, to its potential energydbvuj5 i vc3iyh07qh*z,xk 94d/*ri r 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

30#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Describe the energy of a cw4p y1s:g0iz5sjl- rl ar driving up a hill.

A. entirely kinetic

B. entirely potential

C. both kinetic and potential

D. gravitational

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

31#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A lightweight object and a very vv3c8 yoyu7k v9 t3f-gheavy object are sliding with equal speeds along a level frictionless surface. They both slide up the same frictionless hill. Wt-g3yvko 7vc3uy 9 f8vhich 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

32#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Consider two masses y: +oiq u ygea*5k4zh7

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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

33#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the principle of conservation of mechanical energy for conservk 5qe1fa4r s*iative forcesqaes4k ifr *15.

该题自我估分: (必填) (满分:1.0分)

绑定到本题的附件链接:
绑定到本题的上传图片: (问答题类型题目图片/附件必须插入上方文本框，否则会被移除题目绑定)

参考答案:

进入本题讨论区，参与讨论

标记此题

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 buildingeyn x(6 :on)ppm7uj se16m9dq , through the air (air friction is present), to the ground below. How does the kinetic energy (K) just before striking the ground compare to the potential energy (U) at the top of the(x9usm 6:) 1 dp7nopmey6nqj e 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 ened9j w7lxsn*e **uije *rgy. Do not ignore air resistance. How much gravitational potential energj*x79* *den*jwlsiu ey 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 gr9mly-b d 2avupp7 2l/cavitational potential energy. Do not ignore air resistancempc-2/9p ul 7vyb2lad. 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

37#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the law of conservee51qrr y:hz,ation of energy.

该题自我估分: (必填) (满分:1.0分)

绑定到本题的附件链接:
绑定到本题的上传图片: (问答题类型题目图片/附件必须插入上方文本框，否则会被移除题目绑定)

参考答案:

进入本题讨论区，参与讨论

标记此题

38#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The quantity Fd/t is9rh), 3*xguo5 r bzj6oc:1si rjeuli 1

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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

39#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the correct unit of powe; cae* xi,;hzmexmv5mr*mp0+ r expressed in SI units?

A.

k g m / s^{2}

B.

k g m^{2} / s^{2}

C.

k g m^{2} / s^{3}

D.

k g^{2} m / s^{2}

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 yuqmt:2+;evoc(p p.g9)z g fiof power?

A. watt/second

B. newton-meter/second

C. joule/second

D. watt

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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*i)8 nbpkk n,k-third the time. To do so, youbkp*8nkik)n ,r power output must have been

A. the same as yesterday's power output.

B. one-third of yesterday's power output.

C. 3 times yesterday's power output.

D. 9 times yesterday's power output.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

42#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

To accelerate your car at a cons a2 hn.s/orxi:tant 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.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

43#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object is lifted vertically 2.0 m and held there. If the ob szo3y0 n5lix3 alz+6mject weighs 90 N, how much wo z+mlszo3 x50 lyna36irk was done in lifting it?

A.

360 J

B.

180 J

C.

90 J

D.

0 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 a+l8o6 iame-vwir a distance of 1.0 m, at a constant velocity of 0.50 aiev6mlo- w8+ 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

45#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 500-kg elevator is pull v4y xv4fs0di0ed upward with a constant force of 5500 N for a distance of 50.0 m. What is 0 x0 svydvi44fthe 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 550;mal3s m t;ez:0 N for a distance of 50.0 tz;am: e 3ms;lm. 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 ab.f;/nd7 xl,2 sqagyq p qz5h l-f;x/for a distance of f qdslyq,a h;;b/f/z57.xlga q-xpn250.0 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 alongzr23;e:drxt p. a7mdh 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 (edk tx;b 5mb9v*(fhmk 3 c2qxdown 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

50#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Matthew pulls his little sister Sarah in a sled on an icy surface (assume no flsg.ne w6fkv 0ke .2-+ool,6zwy/mr 0 x aoz.driction), witman/,x le26 .-6so .zkdf ow0vr +yolw0g.ez kh 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 graph in ( s+l+xsflgs6h -u2 xhFig. 6-1 shows the force versus the object's position. Find the work done when the obj 6lsxf+usgh- h(ls+2xect 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

52#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in qpa+k)x 7-navy ca -mx yz00q/the direction of the force. The graph in Fig. 6-1 shows the force versus the object's position.7p)m-n0 a-avk +xxy/ zqay0cq 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 forgsr;8p6vd(q+ x ao3dj ce. The graph in Fig. 6-1 shows the force versus the object's posit(j8s xq 3 vpro6a;+gddion. 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

54#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A force moves an object in the directet yt( ,1gojhtx d6h2eg7i d/7ion of the force. The graph in Fig. 6-1 shows the force versus the object's position. 6g h,7ege1 d/d7 tht2o(tyjxiFind 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 d0f8xr7+t tsr:h* tsmmove a 55-kg cart (initially at rest) across a 10 m level surface. What is the final kird :r0m fh8t* ts+ts7xnetic 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 (initiallv- ,b qm;d9xegy at rest) across a 10 m level surface. What is the finam d,evg-;b 9qxl speed of the cart?

A. 73 m/s

B. 36 m/s

C. 8.5 m/s

D. 6.0 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

57#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10-kg mass is moviw4n +6( g/vj27.y rdqvhpybhx ng with a speed of 5.0 m/s. How much work is required to stop the / bq 4 2h+6rvvwnyjph7(ygx.dmass?

A.

50 J

B.

75 J

C.

100 J

D.

125 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

58#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If it takes 50 m to stop a car initially moving at 25 m/s, what distance is refh bbbh4;l; a5quired to lb;5h;b af b4hstop a car moving at 50 m/s under the same condition?

A.

50 m

B.

100 m

C.

200 m

D.

400 m

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

59#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring-driven dart gun k87ehlh*gbz qym( 5o .propels a 10-g dart. It is cocked by exerting a force of 20 N over a distancl(z5qm k*bhh8 .gy7eoe 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 component of 6slo2dw4c5m. j 4ie z0e0 N. The force is applied to a box which rests on a level frictionless floor. The cart starts from rest, and moves 2.0 m horizontally along the floor. What is 4 j e 24z05iw.lecsodmthe cart's final kinetic energy?

A.

200 J

B.

160 J

C.

120 J

D. zero

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

61#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An arrow of mass 20 g is eqc*bgj v i(7.ex i3gp 9;bqs6shot horizontally into a bale of hay, striking the hay with a velocity of 60 m/s. It penetrates a depth of 20 cm begc63qx ;p e9jesbbg7qi vi.*( fore stopping. What is the average stopping force acting on the arrow?

A.

45 N

B.

90 N

C.

180 N

D.

360 N

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 fxbd,*n nuuqvf82 7 0sjvs wr).loor to a height of 13.0jdnv u.vx0)qfbsu2rs , n78* w m above the floor. What is the change in gravitational potential energy?

A. zero

B. 1030 J

C. 1176 J

D. 1910 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 long ,f)u9kj,cdfds qw6)b1 d7k2spk8b u qand rises 2.0 m. ku8jf27 wsqc,b1p )dd kuk)f ,s9bd6 q If the plane is frictionless, how much work was done by the push?

A.

1600 J

B.

800 J

C.

400 J

D.

100 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 s+w:sb3e3zo. c:qsrqs6r:c f ktretch 2.0 cm. What is the spring cons.q3 rfs:63cs cqo sr:b:ezk+wtant?

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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

65#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring is characterized by a4d*ov x34gf ep spring constant of 60 N/m. How much potential energo p*d43v4xf egy does it store, when stretched by 1.0 cm?

A.

3.0 \times 10^{- 3} J

B.

0.30 J

C.

60 J

D.

600 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Calculate the work required to compress an initially uncompressed spring with a /s3 ww e-hn8ezeikbv gk,:zm8 02ro*gspring constant of 25 N/m by 10 ceh2obs3gezk* -e8 w mg ,vkzr: n0/iw8m.

A.

0.10 J

B.

0.13 J

C.

0.17 J

D.

0.25 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

67#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What work is required to stretch a uj44j ztlc 6(i+tab2g w*y/fwspring of spring constant 40 N/m from x = 0.20 m to 0.25 m? (Assume the unstretched position is ju2z(gy cab/*6jwt 4i+t4fwlat x = 0.)

A.

0.45 J

B.

0.80 J

C.

1.3 J

D.

0.050 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

68#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A spring with a spring constant m. h je7jhlpdnh3o; 8h ;+rms:of 15 N/m is initially compressed by 3.0 cm. How much work is required to com eo7h3+;dm;l h8hm:j jp.nhsrpress the spring an additional 4.0 cm?

A.

0.0068 J

B.

0.012 J

C.

0.024 J

D.

0.030 J

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 ic;gu v 8zer4n(9 a*mz3yxcuc4s the speed of the skier on reacyuv(gucc*49z8 c4e n;zamxr3hing the bottom of the slope? (neglect friction)

A. 22 m/s

B. 31 m/s

C. 38 m/s

D. 41 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 anv,kgdr 8u/g k8lx y;5;ny cgra2 /p/zu initial speed of 4.0 m/s.58yp/8 ux r c;;/ g kkgy/,gndluz2var Neglecting friction, 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

71#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An object slides down a frictionless inclined plane1ds*r 3 qlxz,r. At the bottom, it has a speed of 9.80 m/s. What is the vertical height of t1x *,rz l3rsdqhe plane?

A.

19.6 m

B.

9.80 m

C.

4.90 m

D.

2.45 m

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

72#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1.0-kg ball falls to theuzztn:5,v c.q floor. When it is 0.70 m above the floor, its potential energy exactly equals its kinetic energy. How fast is it monz v5.uq,c tz:ving?

A. 3.7 m/s

B. 6.9 m/s

C. 14 m/s

D. 45 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 u1l*qyk7/ho pzif k ;5up from ground level with a kinetic energy of 40 J. At the exact top of its trajectory, its total mech k*iof qu;zhpy75 1l/kanical energy is 140 J. To what vertical height does it rise?

A.

1.0 m

B.

10 m

C.

14 m

D.

24 m

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

74#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A projectile of mass m leaves the ground with a kinetic energy of 220 J. At n.ef .).bj4a ljxp)qrj9 tus +the highest point in its trajectory, its kinetic energy is 120 J. To what vertical height, relative to its la ej. bspj+jqu4a fxtl)9..nr)unch point, did it rise?

A.

\frac{220}{m g} m

B.

\frac{120}{m g} m

C.

\frac{100}{m g} m

D. Impossible to determine without knowing the angle of launch

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

75#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster startt ,y sowirmgnrn: :p w7..t;5:kky+ces from rest at a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect yosw:gec,w+kt .7.rni;my5 tk:p rn: friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?

本题所包含的其它图片:

A. 14 m/s

B. 17 m/s

C. 24 m/s

D. 30 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

76#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A roller coaster starts wi1 g )z 50r:s(sbnwisqgsh(9pgth a speed 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 5sss 1pw9g(:r( i)hzb0 qgsng 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 bot8y wvqt51jy2)vbt 4 fbtom 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, which is 41)wvyvf8b 5jbqt 4y2t5 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

78#

( 1.0 分) 切至整卷模式搜藏此题

What is the minimum speed of the ball at the bottoflq ,a qs.(xj,m of its swing (point

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

80#

( 1.0 分) 切至整卷模式搜藏此题

难度:2

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 0.16 m,x *oyfwyyirxj6*(1 n away from the vertical axis and released from rest. What will be its speed at the bot(roiwy6x j, y* *fnxy1tom of its swing?

A. 0.2154 m/s

B. 0.574 m/s

C. 0.861 m/s

D. 0.718 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 uncu;+n dj7-m l3glidzg4ompressed horizontal spring with spring constnzddg i 3;+74-jmullgant 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 vlv-z 8 kw1iu jf9xeh2 *o+j;nkg car to stop for a red light. What wor18u*z n ikl;ev+fvhoj 29w-xjk 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

84#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The kinetic friction force between a 60.0t-2 1fwx/ij swcisi* vw251u x-kg object and a horizontal surface is 50.0 N. If the initial swjsxw5 c-i*w1i t2 v/f xi2su1peed 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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, levelqks v-p6 /m2hl surface. It has 24 J of kinetic energy. The friction force on it is a constant 0mvp k-lq6sh2/ .50 N. How far will it slide?

A.

2.0 m

B.

12 m

C.

24 m

D.

48 m

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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-kns )pnsush7gv+ d5cuu nyhz.5j8 8 zv2 21iv-bg mass on a level surface. The coefficient of kinetic frictionh d 28s -hg n)p+u v5sz8yv7 12jizcuv5ubsnn. 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

87#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 60-kg skier starts from rest fr 5 c 4wju4 n;c+,.bqayfii)tm,hjm7poom the top of a 50-m high slope. If the work donto,qmymw7phccb j5nu; i 4)j.,if4a +e by friction is

- 6.0 \times 10^{3} J

, what is the speed of the skier on reaching the bottom of the slope?

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 plan3 i8jny/ uz6s c*u*edge. The plane is 4.0 m long and rises 2.0 m. It requires 3200 J of work to get the box to the top of the plane. What was the magnitude of the ave36yud ignz e us8cj*/*rage friction force on the box?

A.

0 N

B. non-zero, but less than 400 N

C.

400 N

D. greater than 400 N

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

89#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2.0-kg mass is released ;f51ihsybwpf*.-fwmgh r+ 0afrom rest at the top of a plane inclined at 20e above horizontal. The;5wmwf0i ybs-h*f.hf+p 1 rag coefficient of kinetic friction between the mass and the plane 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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习全部题目来源于题库网 (https://tiku.one)，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

90#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 30.0-N stone is drxi nc:o9k /9 sfi-(lxfopped from a height of 10.0 m, and strikes the ground with a velocity of 7.00 m/s. What average force of air friction ck9f:/(f-o 9sni lx ixacts on it as it falls?

A.

22.5 N

B.

75.0 N

C.

225 N

D.

293 N

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

91#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

At what rate is a 60.0-kg boy using energy when nr/c k1dqj*i7e* 3 d8r vfvy*lvy38 nyhe runs up a flight of stairs 10lvyr v f1qd*n7 r3d83yecki*v8yj/n* .0-m high, in
8.00 s?

A.

75.0 W

B.

735 W

C.

4.80 k W

D.

48 W

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 n*wt*k toxz c.8 v+/qsvelocity of 5.0 m/s. What power must be delivered to the objn ts+vqz* x8 .w*/cotkect by the force?

A.

0.50 W

B.

1.0 W

C.

50 W

D.

100 W

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 ams zmhu 1 kbp6oba*njkf+/(r5qn6+ )m 1.0 hp motor that runs for 1.0 hr? (1 hp = *(o61+mh n j )+mu6fk5pbm bzksqanr/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

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

94#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A cyclist does work at thqjlb) 3n rz0tkh+blc7 0hg.8 h.u,rrde rate of 500 W while riding. How much force does her foot push with when she is traveling at 8.0 m/0rrhh.jg kn +7z)8ul0tq3 blcbhd,.r s?

A.

31 N

B.

63 N

C.

80 N

D.

4000 N

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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/u,f4/bc 2n:c,k kji vps in 7.0 s. What is the average power delivered byk/,2b fjkcvp4 ,:c nui the engine? (1 hp = 746 W)

A.

60 h p

B.

70 h p

C.

80 h p

D.

90 h p

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

账号		自动登录	找回密码
密码			立即注册

未使用图片

本次作答已使用

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

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