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 object when its velocity is dou 7juxf6te83spbled?

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 property of matter y,rp;ta5 sk c;is one that does not depend on the quantity of matter present. Wkr ac; 5;sy,pthich of the following properties is NOT an intrinsic property?

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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. Assume the s-u/ v9 olmq/ 6l8ai/ryvi7gaEarth has mass a i//q vvr omi 9/lu7a8-y6lgs $5.98 \times 10^{24} \; kg$ 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#

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09.12: A 5.0 kg sphere is in free fall near the surfacehul sc*dnb* o9+m7gm 4 of the Earth. What is the magnitude o*dg +msbn9ml4 u 7ch*of the gravitational force acting on the earth 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 possible for an object’s velocity to incoze,a xtv+t8,f ,3zsirease while its acceleration deca+s8ozt, ,3fv zei,tx reases?

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 particle undergoes erratic motion. At every point krt)x g8k,t) 9z-:ofc2sa aotin its motion, the direction of toaskraf8o9t : c-2gtt)k ,x )zhe 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 suspended in the air at dzlj- u;6-d ngthe end of a string held by a person. The person pulls on the string uniformly accelerating the block upward for a short t 6djgz-d; -unlime. During this time, which one of the following choices correctly identifies the Newton’s Third Law pair force to the force of the 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 followingcq 33o9v;sb ubfw 2lf- situations is the net force constantly zero on the obc9 ;f- wlvqbb3 u2sf3oject?

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 free fall close to the negz8 *hmqpmkl t b,x.u6 i)1l*,m1qy ground. A person intervenes and slows the objeztie 1lxyu *qq6 nlk,.8)*1h,gmm pbmct 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 magnitude 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,lib i.+ +7s yptgjt5:p*k5t fg F1 of 30 N, F2 of 50 N, and F3 of 70 N, acting on it. The magnitude of the rgp7b ity+pjk.+:5tfgi*5l t s esultant 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 Newto.vzvus yk /eyob / 6jnhl,b.56ns and a force of 10 newtons can be combine to form a resultant with a mag.5usen, / y 6.6vz/l bvjoybkhnitude of which of 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 statements3lqztvm 5ujacqsn+ za *8z9j uv54(0y is most closely associated with Newton’s Third Law of Motiosnc0y*5q v+ 98zvqmza4u zl5jjtu( 3an?

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 does6 mzy+u,, (cgidk4)uvc2rq o:kavj9s not cancel 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 fzbgc,r c pll8q 224n+vloor of an elevator. The elevator is accelerating upward. Which one of the following choices best represents the Newton’s Thil2n+cc8vpzb,rlg q24 rd 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 downward through the air with constant speedhik;m1s+o 80gi ecfk1 . Which one of the following choices correctly describes the Newton’s Third Law pair force to the afk1ci+g1o k ie ;m8hs0ir 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 by a pitcher with a speed of 35 m/s. Th qa4zdk7qbg5 hic c;f3i jn,*2e batterswings and hits the ball. The magnitude of the force that theg 3f cb5k;7nz,dq2j *4iich aq 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 2ad87mtdgc5 s icu (r2on a table. On top of the book is a calculator, also at rest. Which one of the following choices is the Newton’s Third 2d2ruc( msgdci7t85a 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 conduct aln3o3(:qwywg l1 gwelf76i4 ing an experiment related to Newton's Second Law. The collected daeon lw71w gwil3 :(q34f6glyata 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.

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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 fo60a iyx. zhjq,rce on an object were doubled while at the same time the mass of the object was halved,then the acceleration of the objy0qi.h ,6zajx ect 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 accelerated uniformly from rest toth,g+ene y: :g a speed of 20 m/s in 10s. The magnitude of the net forcg+e,:en ty :hge 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-trailr suf c-u6:gm8er truck is traveling down the road. The mass of the trailer iss -cru:8u m6fg 4 times the mass of the tractor. If the tractor accelerates 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 fo 2z9b,:obap*u7j fon 0ddq 7qyllowing principles best explains why large tractor-trailer trucks gene2b7,pdq o9 yno0 qj:f*azdbu7rally 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 red d6enux0p ps.55c .jest on a frictionless rink throws a 2 kilogram ball, giving the ball a velocity of 10.0 m/s. Which statement describes the subsep06 ue5ns. 5de pxdcj.quent 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 sureve *9x ucfbvq5+;+jz face of the earth with a weight of 100 newtons is accelerated atu v5fqz*bxj+v; c9+e e $4\;m/s^{2}$ . 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 usxh7i5 lub(c js-ye;t/b 8x) )mm/hz 1200 kg is accelerated from rest by a constant force of 2400 N. What is the speed of the car 8.0 s aftcyxixltbsmjzh //)s(u7;b58 )uhm e- er beginning?

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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/s sl,gtj.royej5-sz vr5*vs1) p ,ye x8puides 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 before coming to r,us,-t1)8pg* 5 jyxrvpsr5 .ezvyeoj est?

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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 initial velocity 4.0 m/s slides 8.0 m across a rough horizon;- ; 4oxpkorc,f5kok gtal floor before coming to rest. The coe;,4opfx ko go;5kc- krfficient 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 person ppw5 mjr+n-52 )1khxpk w+vk idushes directly to the right on the box with a force of 60N.+im5k5 pwp kwvx+j1 2- hnkdr) 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?

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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 mo:erb3 t0rp4bumt6 t11 rm1 vkiving 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 coeffi t1t4rbm rv:km1t 0ieu6rbp 13cient 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 wu3p 7 y2b(jk2jweye0 ice at a speed v with its brakes locked.y7ywej( 0ub2kjw 2p3 e 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 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 m slides across a patch of ice at a speedab/zplh(p1 p7bvvdqhl9r3sa 9 (*d/c 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 dra(//z*q7pbcp9b1vd9 vd (h lp a3rhlsy 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 makes an emerge2gd*hha 2pz+hncy stop by slamming on the car's brakes and skidding to a stop. How far would2gp+hz2*da hh the car have skidded if it had been traveling 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 carefui04 7ufxqrgc7r9a 5nzlly control each of the following devices. Which of these devices can cause an acceleration in a mi za7un4 r95r 7fqcxg0oving 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 rocket with a weosmp t,e 3 msp)4f9x*night of 15000 newtons is 24000 newtons. About how much time is neede9t 4m*omspp, xes3)f nd to increase 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 * :a5;6ev rpk41qwgwskz2 ica(wxw t+the right across a horizontal floor. A 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 fo*vwcg2w 1(wit6ap+k4kxzs ew a;q:r 5rce T. Given that there is friction f 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 coaster tra .viagqcst;izt5f :;f1j( 8zrcks of equal length. Assume that on all t8cgzs.;t;15vijif:za(t fr qracks 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 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 coasterjycwd1 yjj -/ (c/f(vh .ats0z tracks of equal length. Assume that on all tracks the roller coaster carts start from rest at the same elevati/w1fjc-y(a(z. 0 tdc sj yvjh/on 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 aloor(0; vjgwwlp p95io ,ng the curved track from point A to point C under the influence of gravity. What would be the direction of the cart's acceleration at poinl0i o9jwg(p ov,rp;w5t

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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 ax,*2wo(aunwl z.,g f 2gzhwa2cross the floor by a rope which makes an angle of 300 withf ao22,nhu.xazg2*zgww ,wl( 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/s 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 .cpr*60a4jv*kg pibd force as shown. Thecoefficient of kinetic friction is 0.30 while the coefficient of st j60.kb4 vd**rcippga atic 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 laix f ksz+v0n29wn 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 x9f +0k 2ivznson 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.k7 fvw21(t in 2je8hdv Which of the following statement n2vwv1d 28 keh(t7fijs concerning this situation is CORRECT?

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 at rest on a sleigh as the sleigh is pulled up a*l obn4wngfdl (u/zf1d(ey61 hill with an increasing speed. Th(*ywlf(uf/n 4go 6l z1 dd1nebe crate is not fastened down to the sleigh. What 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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