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 dr* s0qrv,9hv xoubled?

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#

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02.14: An intrinsic propertyrb//n3-sl5(sdp m imyawp :7)+cggzb of matter is one that does not depend on the quantity of mattecs -w g7gp/bm rs/+)ylpa d(zb35nmi:r present. Which of the following properties is NOT an intrinsic property?

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3#

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04.16: A 20 kg boulder rests on the surface of the Earth j bus w3z;i,7x,g(kfgr9hn8m. Assume the Earth has magnbri g,xh8ks73fz,j;u( mw9ss $5.98 \times 10^{24} \; kg$ 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 spherej.pn8)1k d w3iw rj)vz is in free fall near the surface of the Earth. What is the magnitude of the gravitational force acting on the earth by the sphere? The Earth ma)i1 pjjzd.w3wk)8v nr ss 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 increase w7o2vx65 ehuot hile its accelerationhox 2euo5t7 v6 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 erratiy5 3e+tuz6dk hc motion. At every point in its motion, the dir+hktdy z6eu53ection 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 suspended in the air at the end of a string held by a per r7kd0p.wv j lrh1o(n3son. The person pulls on the string uniformly accelerati7l k31hpdnj0w or.vr( ng 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 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 follovxdej jv,kr +8 t0r7z 9swselj45xy)5 wing situations is the net force constantly zero on thevzkj, 48d yr tjvw7rx+s9 sj5l5x) e0e 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.

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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 fal8e:u wd :+lx njh+(c0tr- vtbpl 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 magnitude of:xbpluj0vte++-htrd 8 n: wc( 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 oirz b(gfsi), - xvc(5ef 50 N, and F3 of 70 N, acting on it. The magn)g iie,-r(b xcfz 5(svitude 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 aer.:hb+xu1bb zdjah7+m2. c y force of 10 newtons can be combine to form a resultant with a magnitude of which+cd ..bh7+e h ub2yma1x:z rbj 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 Newt1k/t1j8ge nep l+ d6kg b--zghon’s Third Law of Mot1gjz e/1dg +p -8lhgt6kn-k ebion?

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 nnj 93;)fu3fw3cy /mtkx7zpet0;t r zmot 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 floor of an elevator. The elevator is acceleratin4m(k07ool ;st9v:l(kqc gb nlg upward. Which one of the following choices best represents the Newton’s Third Lt70 ( g4v o9mlcsn q;klbo:(klaw 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 f5kc,zw:uf*h ;3bwv5d:,jap9 fzyipm :rv 3 wthrough 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 on the skydiver during the fallk;: r,:vf9wp*wfzfi: v,y p 5budc 3h5w3ja mz?

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 byaj nf3uzw6 7zzh*q+b z :qf;br9g6or/ a pitcher with a speed of 35 m/s. The batterswings and hits the ball. The magnitude of the force that the ball exerts on the bat is alwnqaz6z6 r w/fzbrg f uqzj: h*9o+3;b7ays

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 the u1acqi2n:5k*a fai2o book is a calculator, also 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 1akf a5quoca2:2i *n ibook?

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 ;pe7dgb 55 qbwclass were in lab conducting an experiment related to Newton's Second Law. The collected data were displayed on the graph at the right. From thep;dbq w7g5b5 is 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 sameugb841whrkp 2 time the mass of the object was halved,then the acceleration of the object8rgph4k b1wu2 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 accelerated1c( dqf4u ne k9pff*9kwpw +*p uniformly from rest to a speed of 20 m/s in 10s. Thdf1f*9pf *kwep+ ( u9wq cp4nke 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-trailer truck is traveling down the road -6cv:el,defa1e,kf ,k1 pbyb. The mass of the trailer is 4 y f pe,,f1aecb,dk k6-vle1 b: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 lz.isiuh n3,wd;o)r( a arge tractor-trailer trucks generally accelerate much more slowly u) owh(d;si3r,aiz. n 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 kizght y2te85: glogram ball, giving :th8 ge2y g5ztthe ball a velocity of 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 with 0ad,vmw/d)a fa weight of 100 newtons is accelerat)vdafa0md /,wed 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 kgak ,lc6c;8r:,q a1cf dif0xmk is accelerated from rest by a constant force of 2400 N. What is the f0,i:cc,x1lc6k;md aqf kr a 8speed 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 horittb9ptz ypi 4de8/e q6j(o.;czontal floor before coming to rest. The frictional force acting on the block is 3.0 N. How far does the block slide before comin j(ttz;.pbi/ 4 c68teq9eypo dg 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 p av3- q/snhrrb+q- u2bai 5m9xp(s)lrough horizontal floor before coming to rest. T n)xr(5i a-mvsplr 2qsb9q3/-hb+ puahe 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 surfaas4xk0cz+;kmfz, hg j4q jeig)a;c 1+. tr(gg ce while a person pushes directly to the right on the box with a force of 60N. The coefficient of kinetic frii e;t g,z0+.;kg j gcax4 gk msf1(+qzrca4)hjction 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 uniform+ s1p 84ivxbh)h 8;zvhuls /zsly 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 f; siuzh/svhzp) 8b84v s+ xhl1riction 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 wibm1(uw1 22ia phyd. gxth its brakes locked. It then hits dry p. iwma1dx(2yhp g2bu1avement 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 ,vq3hf pg:za 7.oi w-.xp mbk/m slides across a patch of ice at a speed v with its brakes locked. It then hits dry pavement and skids to a stop in a distanced. The:oh-z /big pmwk3 ,.f7axqpv. 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 by slamming on th1 n,tns+zg u8yw/k(.xs3hlu8tztfto z wq6 , *e car's brakes and skidding to a stop. How far wouldn* zss gwnz6l 1+3/,f, kxqh.tuzut8o(twyt8 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 carefully control each of the fd9i90ocf aosr 1hqlto*7 c c(d2bw-b )ollowing devices. Which of these devices can cause an accelerationo1c-7b ih2 9a bd*tlfsc 9(0qowoc)d r 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 fwd(+*zu rok(d- o5 ga.0rqgc newtons. About how much time isgq kgfo+z o cr*-( w5.0udd(ar needed 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 w0em fcfy(n03c k*d w. 5hpj;qmva.gi a23 8bbacross 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 a.bbgv2p5 j em f3a(3k w ydh8*m0f0iwcn.q;acs 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 lengtht( ik+la;v6 uzmb8a 9u. Assume that on all tracks the roller coaster carts start from rest at the same elevation and moves frictionlessly over thzumak 9vl8(i+bua; t6e 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 equal length. A -yc6u7nyx4 ;jn sa6*r jwhpi.ssume that on all tracks the roller coaster carts start from rehj 66cjn 4.p7 yn- ryiaw;*xsust 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 rollerco k g.zarv/doli /s3i39aster cartrolls frictionlessly along the curved track from poinv/3g9 /is rdk3 al.zoit A to point C under the influence of gravity. 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 dragged across-pqihln)w0a1ou wm *( the floor by a rope which makes 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 0aw )1mwou -(iq* hnlpcrate 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 pucysbxb1qe z.k68 9xp;zze52j zz2p8ashed 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 block after a time of 1 see;b2 pzc5q1 6zs8y 2.j kzexz pab89xzcond?

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*.(mtm,ptmj0ut:i :jd h mq*t 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 the lawn mower. Which of the following relations among the various force magnitudes, W, f, N, P is Cj (h.*itjm:m, :um*dtt0qm tpORRECT?

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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 omb8-p; 1jj ykx. ups+on a table. Neither is moving. Which of the following statements concerning this situatix.spmk8bu1 jp+j -yo ;on 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 slei5:l*ofl bix l lbav 00kt1+za9gh as the sleigh is pulled up a hill with an increasing 1 i*bkz5v+at 0alxb :l9ll0ofspeed. The 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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