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

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1#

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99.36: What happens to the inertia of an objecb0or)7rk1j yqir0m *fm ;(, w:j rpfoxt when its velocity is doubled?

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

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2#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

02.14: An intrinsic pro +y +ztcnfz/r5 +mkir8perty of matter is one that does not depend on the quantity of matter present. Which of the following propertkcif+zr5ty + 8mrnz/+ies is NOT an intrinsic property?

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3#

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04.16: A 20 kg boulder rests on the surface rls-nghbzit oy 70:d j40eq25 z n:n4uof the Earth. Assume the Earth has mass nony2sn07jh-4rli eq0 :5b:u4zzdtg $5.98 \times 10^{24} \; kg$ and $g = 10\;m/s^{2}$ . What is the magnitude of the gravitational force that the boulder exerts on the Earth?

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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 is9v ztr//ts9 3z31epq usseod2 the magnitude of the gravitational force acting on the earvz3t3dqo r9u /s/stees12 9 pzth by the sphere? The Earth mass is $5.98 \times 10^{24} \; kg$ .

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5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

00.09: Is it possible3/ps ki(20q,jkxx2 wa+visk n for an object’s velocity to increase while its acceleratiopx3kkws,nv2/ s+j q ia(i0xk2n decreases?

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.

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6#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

00.11: A certain particx2g 5f 3ybfn8qle undergoes erratic motion. At every point in its motion, the5 fy x82qfng3b direction of the particle’s momentum is ALWAYS

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

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7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

17.14: A block is suspecgy1w u5)ae6w4er8y f nded in 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 th16uw4yr) wgc8ee5 yaf e string 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

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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 situations is the net force const/p j v3mr 2bg2+yzc*ecantly zero on the objectve j2cy cp3b2zg/mr*+?

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.

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9#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

13.28: An object is in f fz1mw(h0fe mw4 6fs3sree fall close to the ground. 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 person? The magnitude of the object’s acceleration is a and the magn mw6em f30h(zfwsfs 14itude of the acceleration from gravity is g.

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10#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

98.03: An object in equilibrium has three forces, F1 of 30 N, F2 of 50 N,i,+ka y9/ ij t5cnm;ya.wn6b s9zgt;v and F3 of 70 N, acting on it. The magnitud/vyjny; tgz5k si;9 aw .6,nita+bm 9ce of the resultant ofF1 and F2 is

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11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

01.07: A force of 6 Newtonkhn-js 7x- y*bs and a force of 10 newtons can be combine to form a resultant with a magnitude of which onhkx* j--7bsy f the following

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12#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

10.06: Which of the following statementacoef2y-4z ;es is most closely associated with Newton’s Third Law of c;e24 -efoa zyMotion?

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.”

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13#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

95.06: The reaction force does not clw2+f t )zjq:pa/ 5lkrancel 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.

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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 eb0hu myf u741alevator is accelerating upward. Whichu1y 4 ma7buf0h one of the following choices best represents the Newton’s Third 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.

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15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

15.15: A skydiver falls downhad;;r bf7 2bwvu/cy .ward through the air with constant speed. Which one of the following choices correctly describes the Newton’s Third Law pair forc . bry;bfh72ucwv d/;ae 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.

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16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

06.08: A baseball is thrown b a4w7bmj8d.qqio 4wg+y a pitcher with a speed of 35 m/s. The batterswings and hits the ball. The magnitude o4b da+jq7o4q8mi.w wg f 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.

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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 a table. On top of3* 0dy2iypxl i the book is a calculator, ayxly *3i0pi 2dlso at rest. Which one of the following 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.

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18#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

05.06: The students in a Physics I class were in lab conductikpt abxvls 7w30x/2 x*ng an experiment related to Newton's Second Law. The collected data were displayed on the graph at the right. From this graph, what conl v0xx2*apxk t/7 3wbsclusions 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.

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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 were doubled while at the samk1 2)y ;jfibuge time the mass of the object was halved,theg1f j)yi2 ;ubkn the acceleration of the object is

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20#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

96.15: A car whose mass is 1500 kg is ghnt.t,puyv4r 3kq,7 accelerated uniformly from rest to a speed of 20 m/s in 10s. r.u3,p7ttq4 yhgk,nv The magnitude of the net force accelerating the car is:

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.05: A tractor-trailerjz ylxzsn:ig/20p wf(xj54 a 1 truck is traveling down the road. The mass of the trailer is 4 times the mass of the tractor. If the tractor acceleratenaxys/xz 4 2flj0zwp (g1j:5is forward, the force that 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.

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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 tractorz 8oy * / usivsxh46s.pc.tbe+3vt+ua-trailer vz4eiu6huc/b+s.pv*. 8a+ tt3osy xstrucks generally accelerate much more slowly that automobiles?

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.

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23#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.19: A 50 kilogram skater at rest on a frictionless rink throws a 2 kilogram (1 (y3ch /ammabrphu2)g :mdmball, giving the ball a velocity of1p :2 )a/ (rmy bghda3m(cmuhm 10.0 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.

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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 *a2kabit8 qw9:m.z h iwith a weight of 100 newtons is accele2aqa8.hw m* iib :9zktrated at $4\;m/s^{2}$ . What is the net force on the object?

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25#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

98.25: A car whose mass is 1200 kg is accelerated from rest by a constant fo36 jr-rth1f*3 znpnsprce of 2400 N. What is the speed of the car 8.0 s after begi z 31p3j-f6pr*t rsnhnnning?

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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/sl1nd,)wz5 bjqlnx8h) slides across a rough horizontal floor before coming to rest. The frictional force acting on the block is 3.0 N. How far does the block slide bn w,ld5nxlh8j z))q 1before coming to rest?

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27#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

95.38: A block with initir3w9 nzh2dq. cal velocity 4.0 m/s slides 8.0 m across a rough horizontal floor before comin93.h zdc2w qrng to rest. The coefficient of friction is:

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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 persox/yiul5.n xy+n pushes directly to the right on the box with a force of 60N. The coefu+xil y x/.ny5ficient 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?

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29#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

13.16: A block initially moving at 8 m/s accelerates uniformly to rest on a hor e cxaw;1-j7sgizontal surface. The block travels a distance of 12.0 m during the slide. Which one of the fol gj7;s-xwe1a clowing choices best represents the coefficient of kinetic friction between the surface and the block?

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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 a speed v withu 0n8m4 n qvh6fpmfj5 8nle 6(uu3*htk its brakes locked. It then hits dry pavement and skids to a s tn45*6 um(pn6 h08ume3vlnjfk fq8hutop in a distanced. The coefficient of kinetic friction between the tires and the dry road is μ .
If the car had a mass of 2m, it would have skidded a distance of

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31#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

00.22: A car of mass ;o9y vh2n3bj sm4 3geem slides across a patch of ice at a speed v with its brakes locked. It then hits dry pavement and skids to a stop mj2eb;9v 3s4geo n3yhin 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

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32#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

04.32: he driver of a car make vyh+9.vb 62mhogh5()zqxm jtv o1u.qs an emergency stop by slamming on the car's brakes and skidding to a stop. How far would the car have skidded if it had been travelingvuh jvhx y5+2 zhv) ogm1.o(tq.b9qm6 twice as fast?

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33#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

99.39: The driver of an automobile must carefully controp1d9 sozs* a:ol each of the following devices.s1 : ozspa9do* Which of these devices can cause an acceleration in a moving car?
(1) the break pedal ( 2) the gas pedal ( 3) the steering wheel

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34#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

00.25: The net force on a rockeour( e-:q:pvu7bxog4t with a weight of 15000 newtons is 24000 newtons. About how much time is needed to increaseqg-r(oe74u: x u :obvp the rocket ’ speed from 12 m/s to 36 m/s near the surface of the Earth at takeoff?

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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 qz6 6*9-/wm/p) usmdkkd5iro-q d dqt6pg n7v person called 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 /7 n56ro qw6)*mks- qukpddmptdz iq 6/9-dgv and the box accelerates to the right, rank the sizes of these three forces exerted on the box.

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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 coaq8kieb8w9)a buk8,y n.yao./6f1dd8 w uius qster tracks of equal length. Assume that on all tracks the roller coaster carts start from rest at the same elevation and movi /dn ,ekwiu b.aaw1)6o88y8f k yq8ub9 d.sques 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

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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 coaster tracks of e mvwpyr1-7tdl*mk gf 9rx5d,0qual length. Assume that on all tracm,f0k -r7m1 l rvdwgt yx59pd*ks the roller 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?

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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 th+;knh4eh gdvc*1fo2xk d 8as 5e curved track from point A to point C under the influence of gravity. What would be the direction of the cart's accelerat+ v cnfxka58eh214os*gdh;dk ion at point

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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 across the floor by a rope which mt4+ hmbg n;9aathp aywuq)oa0*.; ra 5akes an angle of 300 with the horizontal. Which of the following would be closest to the 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/snhba +9p w.*u 5 )4g0ar;ot ;hqmyataa as shown in the diagram?

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40#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

04.40: A 6.0 kg block initially at rest is pushed against a wall by a 100 N f 5c pt:agv,)fmorce as shown. ampt f), gcv5:Thecoefficient of kinetic friction is 0.30 while the coefficient of static friction is 0.50. What is true of the 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.

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41#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

05.10: A homeowner pushes a lawo,.qalaj;7xkirzxz/.t w17 qn mower across a horizontal patch of grass with a constant speed byj 7rx.toaz k1lxi qq .w;/,za7 applying a force P. The arrows in the diagram correctly indicate the directions but not necessarily the magnitudes of the various forces on the lawn mower. Which of the following relations among the various force magnitudes, W, f, N, P is CORRECT?

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42#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

06.14: A book leans against a crate on a table. Neither is moving. Which of ztz7 d3xnpvh8v-gti8d.6jc0 the following statements concerning this situation is CORRECT?pgvdtc. 6d -3z0t ji8 zn8hxv7

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.

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43#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

06.15: A crate of toys remains a:s 8uhzp9k7lw pa9qz;6p0. hjq2u ezdt rest on a sleigh as the sleigh is pulled up a hill with an increasing speed. The crate is not fastened down to the sleigh. jel 9: 6h.u 7hppqsqpwd;0928 zzzkauWhat force is responsible for the crate’s increase 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

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