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 th/0dp a o)p8 m:n:;cvlwrh4osr e inertia of an object 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 property of * wp 1heri:pa(matter is one that does not depend on the quantity of matter preshwaer:* 1p(i pent. Which 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 2xrapr 5cl2,9to4g xs jbk l6+the Earth has mass gtrp95 ax2sco2x jlk,lb+ r64 $5.98 \times 10^{24} \; kg$ 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 i 4 /jwiaj /*yd9fcnz+z)2x r3pa6ncnws in free fall near the surface of the Earth. What is the magnitude of a/)cx2nzri39 ncjwd / y*z+pw 4 6nafjthe 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 in- rwzm(h e)y(qg(yv7f crease while its acceleratiovw7 y-e(frg(myh(z q )n 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 particle undergoes erratic motion. At ever)p0 vn0v 5rk ibgor1v.y point in its motion, the direction of the particle’s mo ikgvn0b5p.0 vr1 r)vomentum 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 ,jf wr*6ub n-t(hj k3dthe end of a string held by a person. The person pulls on the string uniformly accelerating the blockh3n d6fbtjw uj*(kr -, 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 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 ofl -at/e j-pjn; the following situations is the net force constantly zero on the objec;atel-pn -j/jt?

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 ground. A person intervenps6w dn-. xr0ues and slows the object uniformly to rest. Which one of the following statements must be true about the magnitude of the acceleration of the objepsd6w.x n- ru0ct 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, F1 of 30 N, F2 of 50 N, c6ykwk z5 nf3yaa59d 0ih. v7mand F3 of 70 N, acting on it. The mag 3k5kazc0v9hnm6dy7fw. 5 ay initude 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 Newtons and a force03h wjfv,n5qk of 10 newtons can be combine to form a resultanthvj,50n3kfqw with a magnitude 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 statements is most closely associated with ( gl22y3kxhs,ko r8 po- i1gib .gr2zkNewton’s Third Law of x2 kr-r gik(, sz8yg1 2 ko2hio.l3gbpMotion?

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 cakzit-aop:z d- 8 be3: llv0,qdncel 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 e76ddk efx9x3 of an elevator. The elevator is accelerating upward. Which one of the following choices best represents the Newt93fkd7de6e xx on’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 downward zln3*pcs5 2 . w;tymkykmbl:0 through the air with constant speed. Which one of the following choices correctly describes the Newton’s Third Law pair force to the air resistance acting l:cb5t; 0m wny slykpz2mk*.3on 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 ths,: zgcgr 9g,ikxu4 n2rown by a pitcher with a speed of 35 m/s. The batterswings and hits the ball. The magnitude of the force tha 2z 4xgsc uig9,r,n:gkt 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 of thnhvkwwqhdg: +;uo pj: 3bkj8 gv9+:.ye book is a calculator, also at rest. Which one ofp+y:3nwbkjdgq;hh +kgw9jo 8:.uv: v 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 Phys25i2 orxxmzphiex /: 6ics I class were in lab conducting an experiment related to Newton's Second Law. The collected data wzxxm :2/xh oir25epi 6ere 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 force on an object were doubled while at the same hiem9wn /9t*x time the mass of the object/m9t 9ewh*x in was halved,then 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 i0 uaak qc,90k4 nvw+mcs accelerated uniformly from rest to a speed of 20 m/s in 10s. The magnitude of the net force accelerating the car is: qw ,nauckac490+ 0vkm

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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-trailer truck is traveling down the road. u9 m(n ylxsc,4fhbz;od 1 k.a3The mass of the trailer mda3hb4ky (u; cxzln. o ,1s9fis 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 following principles best explains why large-abpbg7:*gn 9pglta(2jgj- x tractor-trailer trucks generally accelerate much more slowly thata*-a 9ltbxgpb( -gjn: j7p 2gg 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 frictioqjbx*5e. 0wu snless rink throws a 2 kilogram ball, giving the ball a velocity of 10.0 m/s. Which statement deq.e5 uwsj0 xb*scribes 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 t-/o pd7(dt3 n uhn -)fkhcuitile77.n he earth with a weight of 100 newtons is accel)k3d/-u7i.tnnhoui-h(ef 7 ptnd 7lc erated 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 re9f8kdjo29 ogjyhn ,,d st by a constant force od,d 82 hjj,fg9ny 9koof 2400 N. What is the speed of the car 8.0 s after 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 slides across a rough hxp *j 5jte:j:corizontal floor before coming to res5tjxc:pe :jj* t. The frictional force acting on the block is 3.0 N. How far does the block slide before 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 initial velocity 4.0 m/s slides 8.0 m across a r6mow:iq b:ab .ough horizontal floor before com bob.:qam:w6i ing 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 onb(csmhzj//2j9np 8af+n 8s pz a horizontal surface while a person pushes directly to the right on the box with a force of 60N. The coefficient of kinetic friction between the box+mah(8n zsbncpfp 2/j98/j zs 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 re /02nn,:legfpre)ekg st on a horizontal surface. The block travels a dist:g/lepnere),f2g n0 kance of 12.0 m during the slide. Which one of the following 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 ar,70q:igys:.yoa a62 pwaby x 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 yy0b26aqras,a:i.w: yg7xop 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 speed v with its cr.a7rc5tr lgi(fpge- 3-ml qc 9pzxs46up 4* brakes locked. It then hits dry pavement and skids to a stoup- mlps7igre r-.lzr(g3fa9c6 tc44 c*xp5q p 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

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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 emergency stop byn+w*8vf(2z74ua uc k xb0gk5faa q3aw slamming on the car's brakes and skidding to a stop.0(wa3vw*xa z7 aaunu4kc 28q g5kfbf+ How far would 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 automobie(:fmxt3 kha.etc )u(24 gswale must carefully control each of the following devices. Which of these devices can chc:xwm g u4)sat2e3(fek (t.aause 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 rocket with a weight of 15000 newtons is 24000 ne4vhdda2*en: y1l5 -obz tca;wwtons. About how much time is ne1c z 4d lybd:tnh 2ae;5-w*ovaeded 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 the right across a horizontal floor. A ;1twual51du uperson called Ted exerts a force T to the right on the box. A person called Mario exerts adaul ;u wt1u15 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, 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 tracks of equal 7v3hwd(ru03phwpm d7 lxx2y 2g0bq5d length. Assume that on all tracks 0h (xm33dl7ywpv dwh2rugp5 0dx 7b2qthe 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 coaster track dnvk0d p god+yk7k6*noa.;y2s of equal length. Assume that on all tracks the roller coaster carts start fdvn.a n2+ kk y p0;kodd6o7*gyrom 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 frictionfn-ypnrd q 42;lessly along the curved track from point A to point C under the influence of q4 ;pyf2r-dnngravity. What would be the direction of the cart's acceleration 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 dra7*bw;v fx;i,xt l7rl48yqgg ggged across the floor by a rope which makes an angle of 300 with the horizontal. Which of the f i;gvlxqy7;gr4xf ,w t*gbl8 7ollowing 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 i:9,,9vfmkf +y yr, gvzgmgad4 s 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 the friction acting on the blodg+ym9f,:rm9y4,ak zvg g v ,fck 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 puja.rh *zc03b8 d f+wuk,rt5cishes 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 magnitude5a zr+r3hkw.f d* t,j0bic8cus 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 againstw betw9 : iyjndh;31t e2lo7tehx+ w++ a crate on a table. Neither is moving. Which of the followitowbihynted ee+3 wxw;h 9lj++ 21:t7 ng statements 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 slpq), ;lp m7t5s5 eqpw1*krt oaeigh is pulled up a hill with an increasing speed. The crate is not fastened down to the sleigh. What fokma lp*r5q p75 qs1e)w;t, tporce 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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