Newton’s law of motion - 无忧得胜-网上国际课程 (5edu.win)

标记此题

1#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.36: What happens to the inertia of an object when its velocity is doubled?,-wiikys l3 m(

A. the object’s inertia becomes 2times greater

B. the object’s inertia becomes 2 times greater

C. the object’s inertia becomes 4 times greater

D. the object’s inertia becomes 8 times greater

E. the object’s inertia is unchanged

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

02.14: An intrinsic property of matter is one that does not depend on the qufb*at, oy 14gmantity of matter yo*a gtmb,f 41present. Which of the following properties is NOT an intrinsic property?

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

04.16: A 20 kg boulder rests on the surface of the Earth. Assumbc(:qvvy 0y,p o-e+stmf4ao 6e the Earth has massvs e-y ,p+qotfob:4yv0(6ac m $5.98 \times 10^{24} \; kg$ and $g = 10\;m/s^{2}$ . What is the magnitude of the gravitational force that the boulder exerts on the Earth?

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

4#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

09.12: A 5.0 kg sphere is in free fall near the surface of the Earth. What,xj- 9 yjqa7kp is the magnitude of the gravitational force actix j7 yp-9akq,jng on the earth by the sphere? The Earth mass is $5.98 \times 10^{24} \; kg$ .

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

00.09: Is it possible for an object’s velocity to increase whilbm2wb gwr11 :7fj:lrn8k v28 yj.swxgc ;+e jle its acceleration de;bwcr2: k .xg n1s jb7y8j2m8l+gw1jlwv f:recreases?

A. No, this is impossible because of the way in which acceleration is defined.

B. No, because if acceleration is decreasing the object will be slowing down.

C. No, because velocity and acceleration must always be in the same direction.

D. Yes, an example would be a falling object near the surface of the moon.

E. Yes, an example would be a falling object in the presence of air resistance.

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

本习题练习题目来源于无忧得胜-网上国际课程 (https://5edu.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，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

6#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

00.11: A certain particle undergoes erratic motion. At every point in its9y 3g4:zdq8 oa; zramd motion, the direction of the particle’s momentum is AL8;4oa:z dg3 ymqrdz9 aWAYS

A. the same as the direction of its velocity

B. the same as the direction of its acceleration

C. the same as the direction of its net force

D. the same as the direction of its kinetic energy vector

E. none of the above

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

17.14: A block is suspended in a7yul(;z0:3krfa+/p wfz bpn the air at the end of a string held by a person. The person pulls on the string uniformly accelerating the block upward for a short time. During this time, which one of the following choices correctly identifies the Newton’s Third Law pair force to the force of the s+(la7 y f/f03unzwkpr:b zpa;tring on the block?

A. the gravitational force from the Earth on the block

B. the force from the string on the person

C. the force from the person on the string

D. the force from the block on the string

E. the force from the person on the block

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

07.18: In which one of the following situati1 qc*uib398-8 b ,flwkqskoatons is the net force constantly zero on at9o- qw3,cs bkk 1i* lbuqf88the object?

A. A mass attached to a string and swinging like a pendulum.

B. A stone falling freely in a gravitational field.

C. An astronaut floating in the International Space Station.

D. A snowboarder riding down a steep hill.

E. A skydiver who has reached terminal velocity.

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

9#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

13.28: An object is in free fall close to the ground)bdgv z7wam 30kw 8m,9*whl nv. A person intervenes and slows the object uniformly to rest. Which one of the following statements must be true about the magnitude of the acceleration of the object as it is being stopped by the p,0vhd* vnawm) w7lbgzk w938merson? The magnitude of the object’s acceleration is a and the magnitude of the acceleration from gravity is g.

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

98.03: An object in equilibrium has thrjc ef/snq4 d,3ee forces, F1 of 30 N, F2 of 50 N, and F3 of 70 N, actinen /c fd3j,q4sg on it. The magnitude of the resultant ofF1 and F2 is

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

11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

01.07: A force of 6 Newtons and a force of 10 newtons can be combine to formiu xtvr5 w. tkp)h,7( 2bwn ,-8sgudvo a resulta,5dg2 b7 uwv-rh ovus,wx)i .(p t8tnknt with a magnitude of which of the following

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

10.06: Which of the following stajhmp :12grsx *pg vhbl)r, hn* +n-6rptements is most closely associated with Newton’s Third Law of Motiog2 nvhx1:lr*h sn* +ph),pbr6 p-mgjrn?

A. “What goes up must come down.”

B. “For every action force, there is an equal but opposite reaction force.”

C. “An object at rest remains at rest.”

D. “The acceleration of an object is directly proportional to the force acting on the object but inversely proportional to the mass of the object.”

E. “The Universe tends toward disorder.”

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

95.06: The reaction force does not -foqkf 4.d05wpqf cv9cancel the action force because:

A. The action force is greater than the reaction force.

B. The action force is less than the reaction force.

C. They act on different bodies.

D. They are in the same direction.

E. The reaction exists only after the action force is removed.

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

14.14: A box rests on the floor of an elevator. The elevator y)x98v w)dzynhn +l 24s: pbn+v 3mtlpis accelerating upward. Which one of the following choices best represents the Newton’s wlln:)) 28t3m 4ynbs+zpvxhny+v9pdThird Law pair force to the gravitational force acting on the box by the Earth?

A. There is no Newton’s Third Law pair force in this scenario.

B. The entire normal force of contact from the floor on the box.

C. Only a portion of the normal force of contact from the floor on the box.

D. The force of the cables pulling upward on the elevator.

E. The gravitational force acting on the Earth by the box.

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

15.15: A skydiver falls downward through the air with constant speed. wlsf /yy.5icp)ue:8 j Which one of the following choices correctly describes the Newton’s Third Law pair: i5. ylcp/)e8wu jfys force to the air resistance acting on the skydiver during the fall?

A. There is no Third Law pair force for this kind of situation.

B. The gravitational force acting on the skydiver by the Earth

C. The force that molecules in the air exert on neighboring molecules in the air.

D. The force exerted on molecules in the air by the ground.

E. The force exerted on molecules in the air by the skydiver.

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

06.08: A baseball is thrown by a pitcher with a speed suqf5 ;tg tkz(o.vn6wt t( :8(j ygj.xof 35 m/s. The batterswings and hitzf:(wyqt86g.xt jsn t;jk5u((v.g ots the ball. The magnitude of the force that the ball exerts on the bat is always

A. zero as it is only the bat that exerts a force on the ball.

B. equal to the gravitational force acting on the ball.

C. larger than the force the bat exerts on the ball.

D. smaller than the force the bat exerts on the ball.

E. equal to the force that the bat exerts on the ball.

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

11.13: A physics book sits at rest on aokb3wey-l n:37(fmz x table. On top of the book is a calculator, also at rest. Which one of the followw7b3:nl-okx3efym z(ing choices is the Newton’s Third Law pair force to the force that the table exerts on the book?

A. The contact force on the table by the book.

B. The gravitational force on the book by the Earth.

C. The gravitational force on the combination of the book and calculator by the Earth.

D. The contact force on the book by the calculator.

E. The contact force on the table by the ground supporting it.

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

18#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

05.06: The students in a Phyqp,:q(c fc( fgl(,hlw -88 ky0pbrlh ksics I class were in lab conducting an experiment related to Newton's Second Law. The q(q,ly8kf l( f-lrph ccg0k bhwp,8 (:collected data were displayed on the graph at the right. From this graph, what conclusions can the students make?

A. The mass of the system was constant.

B. The acceleration of the system was constant.

C. The force acting on the system was constant.

D. The force acting on the system is not related to the acceleration of the system.

E. The force acting on any system will always be less than 20 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

19#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.03: If the net force on an object wer;fd fognqpdlg(+ 2.8, .gmdh 4 zhk6ffe doubled while at the same time the mass of the object was halved,tmpz ,kn(;d64hf8o g gh d.lq. 2fgfd+fhen the acceleration of the object is

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

96.15: A car whose mv r/ sp(d6+y xq,d imly+s(m2mass is 1500 kg is accelerated uniformly from rest to a speed of 20 m/s in 10s. The magnitude of the net mid6 q /vrd,ssx(m ++p(yl2myforce accelerating the car is:

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

99.05: A tractor-trailer truck is traveling down the road.m 0ixg1 zxkq9j5a:zq 6 The mass of the trailer is 4 times the mass of the tractor. If the tractor accelerates forward, the force thatziq:x0a zjx 6kqg9m1 5 the trailer applies on the tractor is

A. 4 times greater than the force of the tractor on the trailer.

B. 2 times greater than the force of the tractor on the trailer.

C. equal to the force of the tractor on the trailer.

D. 1/4 the force of the tractor on the trailer.

E. zero since the tractor is pulling the trailer forward.

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

本习题练习题目来源于无忧得胜-网上国际课程 (https://5edu.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，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

22#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.16: Which of the following principles best explains why large tractor8b zy2qlt 8tsy7 c0;zp-trailer trucks generally accelerate much more slowly that aut z8p 0yztty8;2sqc7lbomobiles?

A. To every action there is an equal reaction.

B. Everybody attracts every other body in the universe.

C. A force is necessary to change the speed or direction of a body.

D. The total momentum of interacting bodies is always conserved.

E. The acceleration of a body is inversely proportional to its mass and directly proportional to the external force acting on the body.

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

23#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.19: A 50 kilogram sk:o 4lz-mttv,m ater at rest on a frictionless rink throws a 2 kilogram ball, giving the ball a velocity of 10.0l: ,t -omvtzm4 m/s. Which statement describes the subsequent motion?

A. 0.4 m/s in the same direction as the ball.

B. 0.4 m/s in the opposite direction to the ball.

C. 2 m/s in the same direction as the ball.

D. 4 m/s in the same direction as the ball.

E. 4 m/s in the opposite direction to the ball.

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

00.13: An object near the surface of the earth with a weight (-duwe )a qjzno8k/u;of 100 newtons is ajade;8w(kq/u)o n- z uccelerated at $4\;m/s^{2}$ . What is the net force on the object?

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

本习题练习题目来源于无忧得胜-网上国际课程 (https://5edu.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，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

25#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

98.25: A car whose mas:vmvh )g* gsrp z 4).g6x4oguyda.a2es is 1200 kg is accelerated from rest by a constant force of 2400 o2evv)4m46r)ugagp * ays.hz g .:gd xN. What is the speed of the car 8.0 s after beginning?

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

98.32: A 3.0-kg block with initial speed 4.0 m/s slides across a r9( g /w,n2x spyvxsq5wough horizontal floor before coming to rest. The frictional force acting on the block is 3.0 N. How far does x(v ngs5s9 wqpy/ 2xw,the block slide before coming to rest?

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

95.38: A block with initiajoqf (v k2zraf1 s1lg3+ iq-a 74gygcm 34cer0l velocity 4.0 m/s slides 8.0 m across a rough horizontal flof3sa0v4z y ggejf4q oi g 31k2a1cmcr7(lr-q+or before coming to rest. The coefficient of friction is:

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

28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

09.21: A 20.0 kg box remains at rest on a horizontal surface while a perso v oyv5a 6i:rxzxjz17;n pushes directly to the rig5xzvv r 1y6z;:xoja7i ht on the box with a force of 60N. The coefficient of kinetic friction between the box and the surface is $\mu_k$ = 0.20. The coefficient of static friction between the box and the surface is $\mu_s$ = 0.60. What is the magnitude of the force of friction acting on the box during the push?

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

本习题练习题目来源于无忧得胜-网上国际课程 (https://5edu.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，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

29#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

13.16: A block initially mov4l)bs njm) e/oing at 8 m/s accelerates uniformly to rest on a horizontal surface. The block travels a distance of 12.0 m during the slide. Which one of the following choices best represents the coefficient of kinetic)/l4j)mo senb friction between the surface and the block?

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

本习题练习题目来源于无忧得胜-网上国际课程 (https://5edu.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，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

30#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

00.21: A car of mass m slides across a patch of ice at r745v7 tzon 5euxksxj d .qzf5akl24(a speed v with its brakes locked. It then hits dry pavement and skids to a stop in a distanced. The coefficient of kinetic friction between the tires and the dry road is μ5u( j5ztoak.rxlzvq7fns7 d x4524ke .
If the car had a mass of 2m, it would have skidded a distance of

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

00.22: A car of mass m slides actnh w(26mijr 1ross a patch of ice at a speed v with its brakes locked. 2r imwh6n1t j(It then hits dry pavement and skids to a stop in a distanced. The coefficient of kinetic friction between the tires and the dry road is μ .

If the car had a speed of 2v, it would have skidded a distance of

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

04.32: he driver of a car makes an emergency stop by slammin a* 52q,qiysn0lk -flig on the car's brakes and skidding to a stop. How far would the car hnql* ayf l0ks-q2,i5 iave skidded if it had been traveling twice as fast?

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

本习题练习题目来源于无忧得胜-网上国际课程 (https://5edu.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，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

33#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.39: The driver of an automobt u)s6f6;d2yt v.qqw*kjf x)sile must carefully control each of the following devic*.qsw y)u;stqk26jv) ft fx6des. Which of these devices can cause an acceleration in a moving car?
(1) the break pedal ( 2) the gas pedal ( 3) the steering wheel

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

34#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

00.25: The net force on a rocket with a weight of 15000 newtons is 24000 n mb( 6 n-0+zntl zthocz-1fjc8ewtons. About how much time is needed to increase the rocz cm+-0 1lb6jf8z-ch tnt(nzoket ’ speed from 12 m/s to 36 m/s near the surface of the Earth at takeoff?

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

07.21: A box slides to the right across a horizontal floor. A person ca 08 9m,,367if;psaixvj y8 evjpp xakflled Ted exerts a force T to the right on the box. A person called Mario exerts a force M to the left, which is half as large as the force T. Given that there is friction f and the box accelerates to the right, rik8a3 ; ,pxvae9ffp sj,p8yvmix 60 j7ank the sizes of these three forces exerted on the box.

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

02.27: The diagram below shows three roller coaster tracks of equal length. A4r -x,rzkztnw 5.x vz(/gm2fc ssume that on all tracks the roller c/ - 2wf.(zv,45ztcx kmnzrxrgoaster carts start from rest at the same elevation and moves frictionlessly over the tracks to the finish.
If all roller coaster carts start at the positions shown, on which track would the roller coaster cart be traveling the fastest at the finish?

A. CartA

B. Cart B

C. Cart C

D. All would reach the finish at the sametime

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#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

02.28: The diagram below shows three roller coa tpvp 4)6v3x vvmj*hx/ster tracks of equal length. Assume that on all tracks the roller xhvmj6v p3pvv*/ xt4)coaster carts start from rest at the same elevation and moves frictionlessly over the tracks to the finish.
If all roller coaster carts start at the positions shown, on which track would the roller coaster cart reach the finish first?

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

38#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

02.29: Assume the rollercoaster cartrolls frictionlessly along the curved t f-xzq/56lltbix5 .dkrack from point A to point C under the influence of gravity. What would be the direction of the cart's accelerationlt-/qi.65xz 5 dlx bfk at 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

39#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

02.40: A box with a mass of 50 kg is dragged acth 9 yu ui8rq+gd,(nng0;6m5yy:w asoross the floor by a rope which makes an angle of 300 with the horizontal. Which of the following would be closest to thuwq:n5ny 0g,so mty6uygd;(+ra8i9 he coefficient of kinetic friction between the box and the floor if a 250 newton force on the rope is required to move the crate at a constant speed of 20 m/s as shown in the diagram?

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

本习题练习题目来源于无忧得胜-网上国际课程 (https://5edu.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，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

40#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

04.40: A 6.0 kg block initiallm-( em 0jy5efcusan /*3 *pghmy at rest is pushed against a wall by a 100 N force as shown. Thecoefficient of kinetic friction is 0.30 while the coefficient of static friction is 0.50. What is true of (mjne5amc* 3y h-/*meps0 gfuthe friction acting on the block after a time of 1 second?

A. Static friction acts upward on the block.

B. Kinetic friction acts upward on the block

C. No friction acts on the block

D. Kinetic friction acts downward on the block.

E. Static friction acts downward on the block.

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

05.10: A homeowner pxtl,. to hf:v80ab .dtushes a lawn mower across a horizontal patch of grass with a constant speed by applying a force P. The arrows in the diagram correctly indicate the directions but not necessarily the magnitudes of the various forces on .8l,htdat ft b:.0voxthe lawn mower. Which of the following relations among the various force magnitudes, W, f, N, P is CORRECT?

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

06.14: A book leans against a/j1xb79/b jf1i2 hmqt daer1o crate on a table. Neither is moving. Which of the following statements concerning this situation is CO9fi1b rq1 j7tb/1 mh xdo2/jaeRRECT?

A. The force of the book on the crate is less than that of crate on the book.

B. Although there is no friction acting on the crate, there must be friction acting on the book or else it will fall.

C. The net force acting on the book is zero.

D. The direction of the frictional force acting on the book is in the same direction as the frictional force acting on the crate.

E. The Newton’s Third Law reaction force to the weight of the book is the normal force from the table.

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

43#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

06.15: A crate of toys remains at rest on a sleigh as the sleigh is))dut*s wldmth5v2, g pulled up a hill with an increasing speed. The crate is not fastened down to the sleigh. What force is responsible for the crate’s inc l*5vh g mdt),d2tus)wrease in speedup the hill?

A. the contact force (normal force) of the ground on the sleigh

B. the force of static friction of the sleigh on the crate

C. the contact force (normal force) of the sleigh on the crate

D. the gravitational force acting on the sleigh

E. no force is needed

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

网页聊天 (离线可收发)

加微信咨询 (申请一对一课程辅导，加本站学习交流群）

电话咨询：

联系管理员：

查看帮助：

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

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

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