Physics Unit7: Linear Momentum - 51fly国际课程 (51fly.win)

1#

What is the SI unit os9v/ +1xv/skx ky mgnu+h8qljg- .d e*f momentum?

A. Nm

B. N/s

C. Ns

D. N/m

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2#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

When a cannon fires a cannonball, the cannon wil m yji5d87ly ))zzks+rl recoil backward because the

A. energy of the cannonball and cannon is conserved.

B. momentum of the cannonball and cannon is conserved.

C. energy of the cannon is greater than the energy of the cannonball.

D. momentum of the cannon is greater than the energy of the cannonball.

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3#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A freight car moves along a frictionless level railroad track at constant spewi57z;1eye d jed. The car is open on top. A large load of coal is suddenly dumped into the car. What happens to the velocity of the; i1edzjy75we car?

A. It increases.

B. It remains the same.

C. It decreases.

D. cannot be determined from the information given

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4#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A child falls sideways off a sled while s k e0dt,l:7iemledding on frictionless ice. What happens to the velo :dkt7lme ,i0ecity of the sled?

A. It increases.

B. It remains the same.

C. It decreases.

D. cannot be determined from the information given

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5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A rubber ball and a lump of putty have equal mass. Theyn-; uot6iwt +, zxude1 are thrown with equal speed against a wall.xenu-w; o tt1z d,i6+u The ball bounces back with nearly the same speed with which it hit. The putty sticks to the wall. Which objects experiences the greater momentum change?

A. the ball

B. the putty

C. Both experience the same momentum change.

D. cannot be determined from the information given

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6#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A sailboat of mass m is moving with a momentum p. How would you 318bx e* swgy7awl3tdrepresent its kinetic energy in terms of these twt 38e1x dw 3ay7bgswl*o quantities?

A. $p^2/2m$

B. $\frac{1}{2} mp^2$

C. $mp$

D. $\frac{1}{2} mp$

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7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If you pitch a baseball with twic7eap/uuo(u tste .t43 e the kinetic energy you gave it in the previous pitch, the magnitud u347tp(eustt.e uoa /e of its momentum is

A. the same.

B. 1.41 times as much.

C. doubled.

D. 4 times as much.

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8#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State Newton's second law in terms o:2d5wy dfp9lvng +z:gbd b i+8f momentum.

该题自我估分: (必填) (满分:1.0分)

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9#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State the law of conservation 8+q67 ovz wios*34lr3shi1xlxaz .dpof momentum.

该题自我估分: (必填) (满分:1.0分)

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10#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The area under the curve on a Forvxl i2vbp/,(e ce versus time (F vs. t) graph represents

A. impulse.

B. momentum.

C. work.

D. kinetic energy.

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11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Which of the following is an achjgd6nno9ke8y ; 2lo(ztyq;2 curate statement?

A. The momentum of a projectile is constant.

B. The momentum of a moving object is constant.

C. If an object is acted on by a non-zero net external force, its momentum will not remain constant.

D. If the kinetic energy of an object is doubled, its momentum will also double.

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12#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A small car meshes with a large truck in a)nl:aub8xc 06u7 :vsia. tqio head-on collision. Which of the following statements concerning the magnitude of the aver.lcb8u nuxvs0:qai) i:to 6a7age collision force is correct?

A. The truck experiences the greater average force.

B. The small car experiences the greater average force.

C. The small car and the truck experience the same average force.

D. It is impossible to tell since the masses and velocities are not given.

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13#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two equal mass balls (one red and the otherz-n b1fc,c 1rpw slfc0/9wx i* blue) are dropped from the same height, and rebound off the floor. The red ball rebounds to a higher position. Which ball is subjected to the greates* xrcf9 zwn-il10 wc1b/fc, pr magnitude of impulse during its collision with the floor?

A. It's impossible to tell since the time intervals and forces are unknown.

B. Both balls were subjected to the same magnitude impulse.

C. the blue ball

D. the red ball

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14#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A Ping-Pong ball moving east at a speed of 4 m/s, co4u3) w i23uwhhzgiomm6 q .fl(llides with a stationary bowling ball. The Ping-Pong ball bounces back to the west, and the bowling ball moves very slowly to the east. Wh ilu63(zwgfm ho h4)uwq2.mi3ich object experiences the greater magnitude impulse during the collision?

A. Neither; both experienced the same magnitude impulse.

B. the Ping-Pong ball

C. the bowling ball

D. It's impossible to tell since the velocities after the collision are unknown.

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15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two objects collide and bounce off each ok. +um5cdtbj od 3j7h4ther. Linear momentum

A. is definitely conserved.

B. is definitely not conserved.

C. is conserved only if the collision is elastic.

D. is conserved only if the environment is frictionless.

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16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 3.0-kg object moves to the right atgan, 5 7kwpol. 4.0 m/s. It collides head-on with a 6.0-kg object moving to the left at 2.0 m/s. W.5, akolpg7nw hich statement is correct?

A. The total momentum both before and after the collision is 24 kgm/s.

B. The total momentum before the collision is 24 kgm/s, and after the collision is 0 kgm/s.

C. The total momentum both before and after the collision is zero.

D. None of the above is true.

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17#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 100-kg football linebackat)un 7,9a qk5 ot42.up*m+vpkl fegjer moving at 2.0 m/s tackles head-on an 80-kg halfback rutop 5kq9 p+kgj 2a eft 7.),u4lmnva*unning
3.1 m/s. Neglecting the effects due to digging in of cleats,

A. the linebacker will drive the halfback backward.

B. the halfback will drive the linebacker backward.

C. neither player will drive the other backward.

D. this is a simple example of an elastic collision.

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18#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

In an elastic collision, if the momentum isg9 ovpdk74o)z 7t v:at conserved, then which of the following statements iovp v:k a)tdz47t 7og9s true about kinetic energy?

A. Kinetic energy is also conserved.

B. Kinetic energy is gained.

C. Kinetic energy is lost.

D. none of the above

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19#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

When is kinetic energo;-tv2lqo;ukd431xipdyp + n y conserved?

A. in elastic collisions

B. in inelastic collisions

C. in any collision in which the objects do not stick together

D. in all collisions

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20#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

In a game of pool, the white cue ball hits the #5 ball and stops, while the #kz tr (fmh:(*if83 nos5 ball moves away with the same velocity as the cue bim:* (nf3t8 z(orkhsf all had originally. The type of collision is

A. elastic.

B. inelastic.

C. completely inelastic.

D. any of the above, depending on the mass of the balls.

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

When a light beach ball rolling with a speed of 6.0 m/s collides with a heavy elq1dcfv4/;fb 0hahh )xercise ball at rest, the beach ball's speed after the collision will be,f1f;)h a vdhl c/0qbh4 approximately,

A. 0.

B. 3.0 m/s.

C. 6.0 m/s.

D. 12 m/s.

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22#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A golf ball traveling 3.0 m/s to the right collidem 5m5gycz*a6f q2 pb+ys in a head-on collision with a stationary bowling ball in a friction-free environment. mzq 2 g*f5mp5+yb 6cyaIf the collision is almost perfectly elastic, the speed of the golf ball immediately after the collision is

A. slightly less than 3.0 m/s.

B. slightly greater than 3.0 m/s.

C. equal to 3.0 m/s.

D. much less than 3.0 m/s.

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23#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A rubber ball with a speed of 5.0 m/s collides head-on elo*2 ;dlltwof2 astically with an identical ball at relto*;2lfd ow2 st. What is the speed of the initially stopped ball after the collision?

A. zero

B. 1.0 m/s

C. 2.5 m/s

D. 5.0 m/s

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24#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A very heavy object moving with speed v col2e : 6p+imrcmbd s8pztr+7 y.ylides head-on with a very light object at rest. The collision is elastic, and there is no friction. The heavypt.m+p2 ys rrzcde 76y8 i:b+m object barely slows down. What is the speed of the light object after the collision?

A. nearly v

B. nearly 2v

C. nearly 3v

D. nearly infinite

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25#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A very light object mozm5jmjc o3( bpv;92d irv sw;:ving with speed v collides head-on with a very heavy object at rest, in a frictionless environment. The collision is almost perfectly elastic. The speed of the heavy object after thmzr mj5:s2vjd;9 op ;c vw3(bie collision is

A. slightly greater than v.

B. equal to v.

C. slightly less than v.

D. much less than v.

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26#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A red ball with a velocity of +3.0 m/s coz6c iq.iz 89pa,y h0hah)oks)ogq b+* llides head-on with a yellow ball of eqz)0okq b+6hayi qsh8zi.9a *),hp c ogual mass moving with a velocity of -2.0 m/s. What is the velocity of the yellow ball after the collision?

A. zero

B. +3.0 m/s

C. -2.0 m/s

D. +5.0 m/s

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27#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A very heavy object moving with velocity v colrvd cx(i;c ;hm ,f-*pqlides head-on with a very light object moving with velocity -v. The collision is elastic, and there is no friction. The heavy objectqcx i-vp * d(rhcm;f;, barely slows down. What is the speed of the light object after the collision?

A. nearly v

B. nearly 2v

C. nearly 3v

D. nearly infinite

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28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

In an inelastic collision, if the rgy71nw((y*x 6g uqmi3stp 6cmomentum is conserved, then which of the following statements is true about kinetic energy? p xt6s*7qr (yuygm1(3ic6nwg

A. Kinetic energy is also conserved.

B. Kinetic energy is gained.

C. Kinetic energy is lost.

D. none of the above

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29#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two objects collide and sticz-k8rmb*: bi .kdsde+qb.w 9 uk together. Kinetic energy

A. is definitely conserved.

B. is definitely not conserved.

C. is conserved only if the collision is elastic.

D. is conserved only if the environment is frictionless.

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30#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 3.0-kg object moveel z4eko+lhe.8 6nk24y fwzy*s to the right at 4.0 m/s. It collides in a perfectly inelastic collision with a ozk4zyw en*+.f46ke2y hlel8
6.1 kg object moving to the left at 2.0 m/s. What is the total kinetic energy after the collision?

A. $72 \; J$

B. $36 \; J$

C. $24 \; J$

D. $0 \; J$

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31#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A small object collides with a large object and sg6 - f0g*swdhy2an9wjticks. Which object experiences the larger magnitud wysnd h g-*g6jw2f9a0e of momentum change?

A. the large object

B. the small object

C. Both objects experience the same magnitude of momentum change.

D. cannot be determined from the information given

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32#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

In a game of pool, the white cue ball hits the #9 ball and is deflected af1 x 4whvjoqy.49 x,)z-a aextt a $35^{\circ}$ angle to the original line of motion. What is the angle of deflection below the original line of motion for the #9 ball?

A. $35^{\circ}$

B. $55^{\circ}$

C. $75^{\circ}$

D. $90^{\circ}$

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33#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Consider two unequal masses, M and m. Which of the following stats/0n)dst 6f( dj2 bydnements is falsesd)02t( dsd6/jf n ybn?

A. The center of mass lies on the line joining the centers of each mass.

B. The center of mass is closer to the larger mass.

C. It is possible for the center of mass to lie within one of the objects.

D. If a uniform rod of mass m were to join the two masses, this would not alter the position of the center of mass of the system without the rod present.

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34#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Which of the following is a false st1/xsr+i u4dpv no:ef0atement?

A. For a uniform symmetric object, the center of mass is at the center of symmetry.

B. For an object on the surface of the Earth, the center of gravity and the center of mass are the same point.

C. The center of mass of an object must lie within the object.

D. The center of gravity of an object may be thought of as the "balance point."

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35#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Tightrope walkers walk wiqwpf1l a/l-4w th a long flexible rod in order to

A. increase their total weight.

B. allow both hands to hold onto something.

C. lower their center of mass.

D. move faster along the rope.

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36#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A plane, flying horizontally, releases a bomb, +nd5.h- xmhp nwhich explodes before hitting the ground. Neglecting air resistance, the center of mass of the bomb fragmedh5px.- nhmn+nts, just after the explosion

A. is zero.

B. moves horizontally.

C. moves vertically.

D. moves along a parabolic path.

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37#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two cars collide head-on on a level friction;1x 0edne:i l5z drpz3-free road. The collision was completely inelastic and both cars quickly came to rest during the collision. What is true about the velocity of this system's center olier;0 ned 53zxp:1z df mass?

A. It was always zero.

B. It was never zero.

C. It was not zero, but ended up zero.

D. none of the above

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38#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State Newton's second law for a system of part0qf86)6tu3ezwpyl;:4 d lcohhv; lpwicles.

该题自我估分: (必填) (满分:1.0分)

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39#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the momentum of a 2000-kg tr5z 1nmh m+a)rluck traveling at 35 m/s?

A. $57 \; kg \cdot m/s$

B. $3.5 \times 10^{4} \; kg \cdot m/s$

C. $7.0 \times 10^{4} \; kg \cdot m/s$

D. $7.0 \times 10^{5} \; kg \cdot m/s$

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40#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1200-kg ferryboat iyjks;3 qo( g *mlad/6ms moving south at 20 m/s. What is the magnitude of its moments j ;/k(ma* gqmy63odlum?

A. $1.7 \times 10^{-3} \; kg \cdot m/s$

B. $6.0 \times 10^{2} \; kg \cdot m/s$

C. $2.4 \times 10^{3} \; kg \cdot m/s$

D. $2.4 \times 10^{4} \; kg \cdot m/s$

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41#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A ball of mass 0.10 kg is dropped from a height of 12 m. Its momentum w is3v- azd6k)ghen it strikes the grounddi6g3asv) k-z is

A. 1.5 kgm/s.

B. 1.8 kgm/s.

C. 2.4 kgm/s.

D. 4.8 kgm/s.

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42#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two identical 1500-kg cars are moving perpendicula; 7y x)s/4,deqofcs, 7kx pkaar to each other. One moves with a speed of 25 m/s due north and the otherk4ck e7xqaps7/o,xsy ,a;)fd moves at 15 m/s due east. What is the total momentum of the system?

A. $4.4 \times 10^{4} \; kg \cdot m/s$ at $31^{\circ}$ N of E

B. $4.4 \times 10^{4} \; kg \cdot m/s$ at $59^{\circ}$ N of E

C. $6.0 \times 10^{4} \; kg \cdot m/s$ at $31^{\circ}$ N of E

D. $6.0 \times 10^{4} \; kg \cdot m/s$ at $59^{\circ}$ N of E

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43#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A handball of mass 0.10 kg, tvf8fg-1n+ pp8 ajnar (raveling horizontally at 30 m/s, strikes a wall and rebounds at 24 m/s. What isn f+jpr1f-v g(pa8na8 the change in the momentum of the ball?

A. 0.60 kgm/s

B. 1.2 kgm/s

C. 5.4 kgm/s

D. 72 kgm/s

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44#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 0.060-kg tennis ball, initially moving atfsilg 3sb .*9 3:jr., zccjdcw a speed of 12 m/s, is struck by a racket causing it to rebound in the opposite direction at a speed of 18 m/sgr*zcicj,js9ds:. l c b 3w.3f. What is the change in momentum of the ball?

A. 0.36 kgm/s

B. 0.72 kgm/s

C. 1.1 kgm/s

D. 1.8 kgm/s

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45#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 50-kg pitching machine (excluding the baseb*:rn z-)nlt ( gne4*iir1z4tr,yksvo all) is placed on a frozen pond. The machine fires a 0.40-kg baseball with a speed of 35 m/s in the horizontal direction. What isr:ts,v)i-4ir*t*nreg1znky(n4 o zl the recoil speed of the pitching machine? (Assume negligible friction.)

A. 0.14 m/s

B. 0.28 m/s

C. 0.70 m/s

D. $4.4 \times 10^{3} \; m/s$

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46#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 70-kg astronaut is space-walking outside the sppjk y .zeka+ mp;a17q(ace capsule and is stationary when the tether line breaks. As a means of returning to the capsule he throws his 2.0-kg space hammer at a speed of 14 m/s away from the capsule. At what speed does thp kp e ;1ay.+j(maq7zke astronaut move toward the capsule?

A. 0.40 m/s

B. 1.5 m/s

C. 3.5 m/s

D. 5.0 m/s

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47#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A small object with momentum 5.0 kgm/s approaches head-on a large ox8 * obbt3t) ta3 fz)7i592ynfgfsmeybject at rest. The small object bounces straight back with a momentum of magnitude 4.0 kgm/s. What is the magnitude of the large object's momentum change28 3ntgt* i9obf7zef3a5fxt)yy)bs m ?

A. 9.0 kgm/s

B. 5.0 kgm/s

C. 4.0 kgm/s

D. 1.0 kgm/s

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48#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You (50-kg mass) skate on ice at 4.0 m/s to greet your fr a:;fvml0yho5 lf r)(-qkw0zriend (40-kg mass), who is standing still, wi; 5 fkrla0mw-rvz)y q0f lho(:th open arms. As you collide, while holding each other, with what speed do you both move off together?

A. zero

B. 2.2 m/s

C. 5.0 m/s

D. 23 m/s

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49#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A car of mass 1000 kg moves to the right along a level, straight road at a sp 8wjwa: cf8yqkd(l dm8arl.9+d 8,m u+hti(cveed of 6.0 m/s. It collides directly with a stopped motorcycle of massw8.f( (l ujwvcltkcd:9i+h day rm+,mq888a d 200 kg. What is the total momentum after the collision?

A. zero

B. 6000 kgm/s to the right

C. 2000 kgm/s to the right

D. 10,000 kgm/s to the right

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50#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1000-kg car traveling at 25 m/s runs into the rear of a stopped car te*mta dwoov-bzp,6 ez-0 rwe (dls 2:8hat has a mass of 1500 kg and they stick toge0e - ov *:zrm8wztab(po se,e-2lwdd6ther. What is the speed of the cars after the collision?

A. 5.0 m/s

B. 10 m/s

C. 15 m/s

D. 20 m/s

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51#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A railroad freight car, mass 15,000 kg, is allowed to coaszfozs i onrpfb66 u)5jl/o;m506my4 ct along a level track at a speed of 2.0 m/s. It collides and couples with a 54uc05op5m jo)bffr i 6;zyl6mo6/nsz0,000-kg second car, initially at rest and with brakes released. What is the speed of the two cars after coupling?

A. 0.46 m/s

B. 0.60 m/s

C. 1.2 m/s

D. 1.8 m/s

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52#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A railroad car, of mass 200 kg, rolls with negligible fricti/jmuob)v82xkx t2; zx on on a horizontal track with a speex/;x2z)mkj8v xo2 ub td of 10 m/s. A 70-kg stunt man drops straight down a distance of 4.0 m, and lands in the car. How fast will the car be moving after this happens?

A. 2.8 m/s

B. 4.7 m/s

C. 7.4 m/s

D. 10 m/s

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53#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 60-kg person walks on a 100-kg log at the rate of 0.80 m/s (with respect tj0r)zc ) ea(eb mef,; mxaj*1eo the log). With what speed does the log move, with respect to the e*zc)ee bmxr jm ,ej0 (f;a)1ashore?

A. 0.24 m/s

B. 0.30 m/s

C. 0.48 m/s

D. 0.60 m/s

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54#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.0-N force acts for 3.0 s on an object. The force suddenly increase,ru1r3iht7+r* izt u.f vrd s u+e1rm0s to 15 N and acts for one more second. What impulse was imparted by these forces t ir1vr u7+s , tr+.3uhe0zmrit1u df*ro the object?

A. $12 \; N \cdot s$

B. $15 \; N \cdot s$

C. $19 \; N \cdot s$

D. $27 \; N \cdot s$

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55#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A constant 9.0-N net force acts for 2.0 s on a 6.0-kg z ;,+c; ylunxxobject. What is the object's change of velocx;c+z ;l,yuxnity?

A. 3.0 m/s

B. 9.0 m/s

C. 27 m/s

D. 110 m/s

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56#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2000-kg car, traveling to the right at 30 m/s, collides with a rue0aaoxr.wg +(ti;je3p+*l 54o xhha ,qc 1obrick wall and comes to rest in 0.20 s. What is the average force the car exerts on the wal;gporhae4u1r, 5 xh at (qxe+ *aw3ioc j.+l0ol?

A. 12,000 N to the right

B. 300,000 N to the right

C. 60,000 N to the right

D. none of the above

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57#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2.0-kg softball is pitched to you at 20 m/sjzdm -jh:3,yk ujekp vd2wb -n)l 8m;1. You hit the ball back along the same path, and at the same speedbj2k-uk1 nz dv-3,d: mj8lym;) jhpwe. If the bat was in contact with the ball for 0.10 s, what is the magnitude of the average force the bat exerted?

A. zero

B. $40 \; N$

C. $400 \; N$

D. $800 \; N$

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58#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 0.10-kg ball is dropped onto a table top. The speeds of the ball rikly.nws5) 8l6ti jg45lcc ga)ght before and right after hitting the table top are 5.0 m/s and 4.0 m/s, respectively. If the collision between the ball and the table top lasts 0.15 s, what is the magnitude of the average force exerted on the ball by the tablejk)li cl5aggc )nt58s.w4 6y l top?

A. $0.67 \; N$

B. $1.3 \; N$

C. $3.0 \; N$

D. $6.0 \; N$

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59#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A machine gun, of mass 35.0 kg, fires 50.0-gram bullets,li1e 2s53uiv0 pd s-pf alb.+j with a muzzle velocity of 750 m/s, at 0p-bl+f2js.e vi3pdiau 1 5lsthe rate of 300 rounds per minute. What is the average force exerted on the machine gun mount?

A. $94.0 \; N$

B. $188 \; N$

C. $219 \; N$

D. $438 \; N$

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60#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A fire hose is turned on the door of a burning building in order to knock rlsj5p; l(9giqpfd. 4/c 3jagthe door down. This requires a force of 1000 N. If the hose delivers 40 kg paj/dij.l 4 f c;(g r3gqpsp95ler second, what is the minimum velocity of the stream needed, assuming the water doesn't bounce back?

A. 15 m/s

B. 20 m/s

C. 25 m/s

D. 30 m/s

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61#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Water runs out of a horizontal drainpipe at the rate of 120 kg per)vl*a lv,8 wxnsb0pd2 minute. It falls 3.20 m to the ground. Assuming the water doesn't splash up, what average force doesda )*,w p80bxsvln2lv it exert on the ground?

A. $6.20 \; N$

B. $12.0 \; N$

C. $15.8 \; N$

D. $19.6 \; N$

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62#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A toy rocket, of mass 0.12 kg, achieq4 gi3ihcha lpsq)5d4u .d; )gves a velocity of 40 m/s after 3.0 s, when fired straight up. What average thrust force does the rocket engines4hipq )d35)hcalu . d ;iq4gg exert?

A. $1.2 \; N$

B. $1.6 \; N$

C. $2.8 \; N$

D. $4.4 \; N$

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63#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two astronauts, of mass jm*n1ngo 92i8ejzhhx/(1pml es 60 kg and 80 kg, are initially at rest in outer space. They push each other apart. What is their separation after the lighter astronaut has moved 12 z /mjgo98 n j2*mpex1h(hln 1im?

A. $15 \; m$

B. $18 \; m$

C. $21 \; m$

D. $24 \; m$

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64#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 3.0-kg object moves to the right with a speed of 2p+ m+cp2eev-vzk k7hka.3uw wesc;7 2.0 m/s. It collides in a per3m u+vhke s7wc wzpk7aev.2e-c2k;+p fectly elastic collision with a 6.0-kg object moving to the left at 1.0 m/s. What is the total kinetic energy after the collision?

A. $9.0 \; J$

B. $6.0 \; J$

C. $3.0 \; J$

D. $0 \; J$

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65#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 0.10-kg object with a velocity of 0.20 m/s in the +x direction makt3,f.y 1 y.0zvb -yg98vw qgfdiaz i+szv,sq*es a head-on elastic collision with a 0.15 kg object initially at rest. What is the final velocity of the 0.10-kg object gz-f bq sw8zv +*vvad 9f.y1z,y i 0y3.qgsi,tafter collision?

A. -0.16 m/s

B. +0.16 m/s

C. -0.040 m/s

D. +0.040 m/s

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66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 10.0-g bullet moving at 300 m/s is fired into a 1.00-kg block at rest. Th 8osg9qtzkb 5m wt19st*:( azq8)sbjrp5m*pie bullet emerges (the bullet does not get embedded in the block) with half of its original spersps8stwmqb8) qt:*g am9ojz5b* tp 15zik(9 ed. What is the velocity of the block right after the collision?

A. 1.50 m/s

B. 2.97 m/s

C. 3.00 m/s

D. 273 m/s

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67#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A proton, of mass m, at rest, is struck head-on by an alpha-particle (which 1/p)t0g0 2x nir dz-lww-twkb consists of 2 protons and 0irwtz2- 0n-d /wwxt lp)kg 1b2 neutrons) moving at speed v. If the collision is completely elastic, what speed will the alpha-particle have after the collision? (Assume the neutron's mass equals the proton's mass.)

A. zero

B. 2v/3

C. 3v/5

D. 5v/3

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68#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 50-gram ball moving +10 m/s coll9mo29cs si6qxides head-on with a stationary ball of mass 100 g. The coqxm s9i62s9c ollision is elastic. What is the speed of each ball immediately after the collision?

A. -3.3 m/s and +6.7 m/s

B. +3.3 m/s and -6.7 m/s

C. -6.7 m/s and +3.3 m/s

D. +6.7 m/s and -3.3 m/s

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69#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

A ball of mass 400 g moving toward the east with kutke6:ga,e 4 a speed of 3.70 m/s collides head-on with a 200 g ball sitting at rest. The col: ae,6g4eutkk lision is perfectly elastic.
(a) Determine the velocity of the first ball after the collision.
(b) Determine the velocity of the second ball after the collision.
(c) Is kinetic energy conserved in this collision?

该题自我估分: (必填) (满分:1.0分)

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70#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2.0-kg mass moves with a speed of/go2 4p,vu mse 5.0 m/s. It collides head-on with a 3.0 kg mass at rest. If the collision is perfectly inelastic, what is the speed of the mass2u/o4g emp ,sves after the collision?

A. 10 m/s

B. 2.5 m/s

C. 2.0 m/s

D. 0, since the collision is inelastic

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71#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 2.0-kg mass moving to the east at a speed o 1hesddgg.s79yxs 0k2f 4.0 m/s collides head-on in a perfectlgyg1d9ds07e .kxssh 2 y inelastic collision with a stationary 2.0-kg mass. How much kinetic energy is lost during this collision?

A. $16 \; J$

B. $4.0 \; J$

C. $8.0 \; J$

D. zero

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72#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A car of mass m, traveling oahh:b4 0roc9ws 41*bnn )xkkwith a velocity v, strikes a parked station wagon, who's mass is 2m. The bumpers lock together in this head-on inelastic collisi4s ab xon 091cohbn 4hkrk:)*won. What fraction of the initial kinetic energy is lost in this collision?

A. 1/2

B. 1/3

C. 1/4

D. 2/3

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73#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

A 15-g bullet traveling 213 m/s in a verth h:jfa)cns416i j 3 yw,lvic.ical direction buries itself in a 2.4-kg block of wood a rest directly above it. As a result, the bullet/block combination moves vertically:h4 cw cj3ljv ).s 6n1i,fyiha upward.
(a) Determine the velocity of the bullet/block combination at the point of impact.
(b) Determine the maximum height reached by the bullet/block combination.
(c) Is kinetic energy conserved in this collision?

该题自我估分: (必填) (满分:1.0分)

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74#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1500-kg car traveling at 90.0 km/h east coll jlr 07 i1ddqj)cc/(zvides with a 3000-kg car traveling at 60.0 km/h south.qc1iz)0crdv ld (/jj7 The two cars stick together after the collision. (See Fig. 7-1.) What is the speed of the cars after collision?

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A. 8.33 m/s

B. 13.9 m/s

C. 17.4 m/s

D. 21.7 m/s

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75#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 1500-kg car traveling at 90.0 km/h east collides with a p2fme3 f: ivaxu57l5l3000-kg car traveling at 60.0 km/h south. The two cars stick together after the collision. (See Fig. 7-1.) What is the dire:mf7 5ueplva5ix2fl 3 ction of motion of the cars after collision?

本题所包含的其它图片:

A. $36.9^{\circ}$ S of E

B. $36.9^{\circ}$ E of S

C. $53.1^{\circ}$ S of E

D. $53.1^{\circ}$ E of S

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76#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two objects move on a level frictionless surface0ming.pny 9ta2 u )8zg. Object A moves east with a momentum of 24 kgm/s. Object B moves north with momentum 10 kgm/s. They make a perfectly inelastic collision. ntp.8ya i9u)n2g0g zm What is the magnitude of their combined momentum after the collision?

A. 14 kgm/s

B. 26 kgm/s

C. 34 kgm/s

D. cannot be determined without knowing masses and velocities

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77#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A small bomb, of mass 10 kg, is moving toward the North with a velocity of 4.0 qgap+r q.8.f yb s swe1giu5+ j,o+)gnm/s. It explodes into three fragments: a 5.0-kg fragment moving west with a speed of 8.0 m/s; a 4.0-kg fragment moving east with a speed of 10 m/s; and a third fragment with a mass of 1.0 kg. What is the velocity of the third1)ifq5wa,es gb +gp gy8n o ..j+rsq+u fragment? (Neglect air friction.)

A. zero

B. 40 m/s north

C. 40 m/s south

D. none of the above

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78#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 4.00-kg mass sits at the origin, and a 10.0-kg mass sitf+2sxrbw.d aw(64pl 33hmf w cs at x = + 21.0 m. Where is the cex.wwdf2wb43cl6rhms 3+(a fpnter of mass on the x-axis?

A. +7.00 m

B. +10.5 m

C. +14.0 m

D. +15.0 m

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79#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The center of mass of a p ,ne2(yh6an1 dhpa:otwo-particle system is at the origin. One particle is located at (3.0 m, 0) and has a mass of 2.0 kg. What is the location of the secono1( nap:eaphn6y2h d,d mass of 3.0 kg?

A. (-3.0 m, 0)

B. (-2.0 m, 0)

C. (2.0 m, 0)

D. (3.0 m, 0)

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80#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Three masses are positioned as follows: 2.0 kg at (0, 0), 2d01qb nphnb ,4.0 kg at (2.0, 0), and 4.0 kg at (2.0, 1.0). Determine the cob qd1n0n 4h,pbordinates of the center of mass.

A. (0.50, 1.5)

B. (1.5, 0.50)

C. (2.5, 1.5)

D. (2.5, 0.50)

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81#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Three masses, 1.0 kgzvvv*j9 p 1*yg, 2.0 kg, and 3.0 kg, are located at (0, 0), (1.0 m, 1.0 m), and (2.0 m, -2.0 m), respectively. What is the location of the center of mass of the 9*vj* g v1vpyzsystem?

A. (1.3 m, 0.67 m)

B. (1.3 m, -0.67 m)

C. (-1.3 m, 0.67 m)

D. (-1.3 m, -0.67 m)

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82#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 3.0-kg mass is posi - hb4kql8e .i-teok 4jfm),sitioned at (0, 8.0), and a 1.0-kg mass is positioned at (12, 0). What are the coordinates of a 4.0-kg mass which will result in the center of mass of the system of three masses being located at the origin,b 4hm4 i)8t-i.e esoj-l,kqfk (0, 0)?

A. (-3.0, -6.0)

B. (-12, -8.0)

C. (3.0, 6.0)

D. (-6.0, -3.0)

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83#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Use Table 7-1 to calculate the position of the CM of a whovh.r ) z1, , lmxdkbj/7ea q)a1k8aghjle leg including the foot when the leg is svz/.r )qhjkm) , l ha8d1x71g,ejkaabtretched straight out. Assume the person is 1.60 m tall.

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A. 0.20 m above the bottom of the foot

B. 0.32 m above the bottom of the foot

C. 0.51 m above the bottom of the foot

D. 0.54 m above the bottom of the foot

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