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

1#

What is the SI unit offjp ll9:8 *k ol3,r(iqvp 4rev,gtw/n 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 will recoil bt b+jr.covt 15zh cce/19zv w/ackward 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 constantibx,yv*n;u ,dmz5vt4p gt -g5 speed. The car is open on top. A large load of coal is suddenly dumped into the caxg,gvudyztp-;b vm5*5in,4 tr. What happens to the velocity of the 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 slewp q65yaas2dl;ta4 g-d while sledding on frictionless ice. What happens to thpawl q2a gs64ady5 t;-e velocity 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 e-i8mppsr s -rmju4wt*uw+ 3a; qual mass. They are thrown with equal speed against a wall. The ball boujp rr*; 8wmmsa+4--sp3 uw uitnces 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 with9)8kfuch +ygcu 3 b k+lv53rwm a momentum p. How would you represent its kinetic energyhr8 k3kfc+v )+glu3mcw9y bu5 in terms of these two 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 twice the kinetixc;4 o9ebx/ 3qh9ryl d i(bw58;asajfc energy you gave it in the previous pitch, theh;ba9 xx ybiq(rja;9 os wlc4538 df/e magnitude 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 teuy: yut56 ubm2rms of 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 of momo t -h/1ntyz+ventum.

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 Force versus time (c0 /z*r3wp- d wasa.+o is.yx1+sheyvF 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 accurate statem;ajkdmwp (zmb zj8,b*w0/,ox d f9lw/ ent?

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 tr v(sd of8dwp(.j hxv-.uck in a head-on collision. Which of the following statements conce(-v .f.v(8xwhpsoj ddrning the magnitude of the average 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 otherrn w2bu3mm,- c blue) are dropped from the same height, and rebou m ,2n3brwm-cund off the floor. The red ball rebounds to a higher position. Which ball is subjected to the greater 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 z3* s .:2hfjil, n0xrxqbqg61;zwwm reast at a speed of 4 m/s, collides with a stationary bowling ball. The Ping-Pong ball bounces back to the west, and :fiz, w n rxg230hsmjxz;w 6. *q1lrbqthe bowling ball moves very slowly to the east. Which 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 i:co-rl+p4 q z(gvnn m d12qv3and bounce off each other. 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 ahrv( h)b o ;b8dsyf v4pr(a +/by)v2bkt 4.0 m/s. It collides head-on with a 6.0-kg object moving to the left a;8(2y b4par+fvdrb )vb h/( v)shobk yt 2.0 m/s. Which 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 linebacker moving at 2.0 m/s tackles head-b7 wmfwkw1p+p)2b9x d on an 80-kg halfback runn7 ppw9xk d)+bww2 bf1ming
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 is conserved, then which of the f8 ilr5j3j-uk zollowing statements is true abzj-85uj klr3 iout 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 energy conserved?+n:;c0:c4a u fgeldss

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 hitso7q8v 2k*ni l9 0,h qcys6sq+g0uzsmc the #5 ball and stops, while the #5 ball moves away with the same velocity as t* 2c7osn 86skulcvz0qsiqq yhm, g9+0he cue ball 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 collideq)+s-5o 7aqdp; a h zyk2ife9ys with a heavy exercise ball at rest, the beach ball's speed after the coe;a iq97spzh)ko5ayy 2 + q-fdllision will be, 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 collides in a head-on 6c;gb n9 4ute e,6jqd l8nm5sxcollision with a stationary bowling ball in a friction-free environment. If t;eb 6, 9ndgtel68jn msq ucx54he 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 elasticawl9cy*xyc /ih6mkozu. g)d. -lly with an identical bc.x 9ychl*z/i)6 -y mo.dgukwall at rest. 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 collides head-on with a very liguod4m;r+k rqn+z:9 0z2 p 4k 5inyzqsnht object at rest. The collision is elastic, and there is no friction. The heavy object barely slows down. What is the speed of the light objd :rnz+kuqyq +pz n4k;5 2zrn40i9 somect 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 moving with speed v collides head-(n vr9tg ;7tnk (rhh/*brbm(/vn*ht ton with a very heavy object a*7m9ht g v v btrkh;h/n( (ttn/b*(rrnt rest, in a frictionless environment. The collision is almost perfectly elastic. The speed of the heavy object after the 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 147ju*zik l lk7jz; /8wgu9z gix yxh9of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of8zu4i w*jy/h jz ux9 gl1ilx7z;kg7 k9 -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 collides head-on wrwwg1yd z dz,e n-x5:6nof+(cith a very light object moving with velocity -v. The collision is elastic, and there is no friction. The hd(+c oy: zn, r gfnz6d5x1wew-eavy 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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28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

In an inelastic collision, if the momentum is conserved, ths+tj1loo pdii9ln 49.en which of the following statements is true about kinetic iloj+491 9s d .oiltpnenergy?

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 stick together. Kinetic ene2yra +2 uncu;ysbp 1+ergy

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 moves to the righ*6y v-5.v;vm// dtwv rqsf0 ;sadl ya(0 xeqtot at 4.0 m/s. It collides in a perfectly inelastic collisi-vs;0yxt(dt vemvorl d a.s5 0*6wa;y/f qv/qon with a
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 4;b nnfr l5 aljg8-kb8object and sticks. Which object experiences the larger magnitude ng5;jn l8rbk4-l 8fabof 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 w,ga3 h ,nflc9 oj g5g1bnh9da.hite cue ball hits the #9 ball and is deflected at 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 massesn/1akhha:w, im*c:vgwkwc ,kxi(m7 :, M and m. Which of the following statements is falsx1 ,:k ,cmhgw*awkna :/ hik:(w7i cvme?

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 dr7u8y0/ oqbrb ny(5 gd: l/apl7yia; statement?

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 widesxxg 88/iuryg u0 8v1q3 n9qth 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, which explodes l1ta)i i41tguq7a)wzbefore hitting the ground. Negletqi1l4ui)a1t zw7a) g cting air resistance, the center of mass of the bomb fragments, 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-free road. The collision was complo7)bsqd.w g: n orv-f;o8k5bgetely inelastic and both cars bq5n ) sgw;.:fo-k7gd ov8orbquickly came to rest during the collision. What is true about the velocity of this system's center of 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 o2.w;nu)x1 uvf+ fckpwc s)/jzf particles.

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 o43bgtg d0k px7a-7 fux47hpoa f a 2000-kg truck 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 is moving south at 20 m/fj t sj(1ifff8)8zjpa t45e7vh/aer1s. What is the magnitude of its momen)t1j f(p j7fajez8ahf4/81r fv s5iettum?

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 -nrw fwwr(pd4 p5rd7+m. Its momentum when it st-(rwd5 d+pr7wp rwfn4rikes the ground 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 perpendicular to each other. One mov6mn)p91vnjl+ s pi0uoes with a speed+ us9imjplpv1non)06 of 25 m/s due north and the other 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, traveling horizontally at 30 m/s, stkt3bju; :nw9t5 ttq1 trikes a wall and rebounds at 24 m/s. What is the change3t t u5wtjt1nb q;tk:9 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 zs3dy;mk/0nghko0( x bq,(svw*d g/ y moving at a speed of 12 m/s, is struck by a racket causing it to rebound in the opposite directioyg3ss,bqmkwhn*(; vz0(0d x / d /kgoyn at a speed of 18 m/s. 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 (exc/ 0 y)hjksvr5 k4z3izpluding the baseball) 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 is the recoil speed of the pitching machine? (Assume negligible friction.5r/3z0kj)yvkz ph si4 )

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-wuwam7)p2n ;l4sop- e walking outside the space 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/u2ao )e nw;-mpps7 l4ws away from the capsule. At what speed does the 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 object at regb3lz ksi)5u1st. The small object bounces straight back with a momentum of magnitude 4.0 kgm/s. What is th5 )ui1skzb3lg e magnitude of the large object's momentum change?

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 gyu x6x/; z39 f4v /basdvmjc1yreet your friend (40-kg mass), who is standing still, with open arms. As you collide, while hold zm ; dc j469xs/xa1uvy3ybfv/ing 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, st iqzo6s/;n9 ugk3f, syraight road at a speed of 6.0 m/s. It collides dn/fsg3 isyu9q kz ;o6,irectly with a stopped motorcycle of mass 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 into8b.j n m p-uu22agc2qo the rear of a stopped car that has a mass of 1500 kg and they stick together. What is the speed of the c-2 b moaqgj2n pucu.28ars 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 -azns f 2rp :ekvl/j1415,000 kg, is allowed to coast along a level track at a speed of 2.0 m/s. It collides and couples with a 50,000-s/r1jnv2 4 -: lzkafepkg 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 friction on 85yr/,eiih3is rgl4wa horizontal track with a speed 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 ,ire wgh8si53iry/l4this 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 resp w 5g;8/zdy .iphmdo3hdz -(zvect to the log). With what speed does the log move, with respect to thm(ov8 dw3-yzh pz5/gi ;hdz.d e shore?

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 objectb+cob+o2 )ei i0cw:nd . The force suddenly increases to 15 N and acts for one more second. What impulse was impd:o2i0+ +e)nib wcob carted by these forces to 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 actsd2: 2.dx;o tb) a f7mrnzlwdf. for 2.0 s on a 6.0-kg object. What is the object's change om;d..:)tl27zf wfxa2 onr ddb f velocity?

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 brick was.e5i keb )bf(; jm(ts-numeco1 k31fll and comes to rest in 0.203u (mcjofst5sk )ikm (e 1;.fbe1 b-ne s. What is the average force the car exerts on the wall?

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 pitchedn)g ll,q29 )ri , olp7;owffwe to you at 20 m/s. You hit the ball back along the same path, and at the same speed. If the bat was in contact with the ball for 0.10 s, what is the magnitude of the average force the bat2f loo7rlwe,9iqn),;pw fg)l 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 right fy*jeh ek. wia,4 k*waw)* gy(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 kyg(fi hw, a*4 *ak*yew.)ewjthe average force exerted on the ball by the table 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, with a muzzle vzbs) x; *qzqo ;lc;2yvelocity of 750 m/ bszxz;v2 )o;;y*q clqs, at the 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 doorg0 00x2msvuygeb.9k/5db q p z of a burning building in order to knock the door down. This requires a force of 100kpzb0dm0q2buy0 .5g e x9/ svg0 N. If the hose delivers 40 kg per 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 mipf ld;s:o unh ;,.o51txz0rr-s c w3omnute. It falls 3.20 m to the ground. Assuming the water doesn't splash up, what average: xruo1mf3h.csdposo- 0nrw5 , ztl;; force does 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, achieves a velocity of 40 m4 ryx;c ex/nwlm 4d6a1/s after 3.0 s, when fired straight up. What ave eynw6 cd4r x1;l/m4axrage thrust force does the rocket engine 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 masses 60 kg and 80 kg, are initially at rest 3; :aoadij n5jal2)chin outer space. They push each othao j;hj :n)a la32id5cer apart. What is their separation after the lighter astronaut has moved 12 m?

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 2.0 m/s. It collides in a7wdv. p bbiw+3uzs c.8 perfectly elastic collision with a 6.0-kg object moving to the left at 1.0 m/s. What is the total kinetic energy afti.c+bwsu pvd .7b3wz8 er 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 orpu.v; 1xxa c), rwad9f 0.20 m/s in the +x direction makes a head-on elastic collision with a 0.1xxa) awvru r;1 .9,pdc5 kg object initially at rest. What is the final velocity of the 0.10-kg object after 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 f7y;/r wxw-8kf 9 pvvgvp47zuiz1 ygf)ired into a 1.00-kg block at rest. The bullet emerges (the bulletz/74p iy yz v89x-v1 vfp)g7wkwu;gfr does not get embedded in the block) with half of its original speed. 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, isz6)d 1vhjh9vqux1xc - struck head-on by an alpha-particle (which consists of 2 protons and 2 neutrons) moving at speed v. If the collisi -hxjqx1vh9d6) uvzc 1on 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 collides head-on with a stationaryzj s4o91u nd2t ball of mass 100 g. The collision is elastic. What is the speed of each ball ij2dno1 4u9 zstmmediately 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 a speed of 3.70 m/sou4 o bq+h; dnrjy8r)srl)94a collides head-on with a 200 g ball sitting at rest. The collision is perfectrs) )drabl4 uo nq9;j4hoy 8r+ly 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 5.0 m/s. It collidessux(.,22d ofg3n llsf zsc3; x head-on with a 3.0 kg mass at rest. If the collision is perfectly f xgclons.; dxfs3u2(3s zl2,inelastic, what is the speed of the masses 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 o4nf lx*h)elwfa 3g t(/-qr7ybgc** kxf 4.0 m/s collides head-on in a perfectly inelastic collision with a stabcx/ lf ywxa*n7lf*3 t*e h(4q g-g)rktionary 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, traveli,k( qu/prfpjem3g f -(ng with a velocity v, strikes a parked station wagon, who's mass is 2m. The bumpers lock together iq3u/(ke-f(gpmpj rf ,n this head-on inelastic collision. 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 ve)ffo x-c,ytv4rtical direction buries itself in a 2.4-kg blv)f o xc4,-ftyock of wood a rest directly above it. As a result, the bullet/block combination moves vertically 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 ata4/v (ye(i n1f qb4d7ia9*ixpu5xeucf4kz6 v 90.0 km/h east collides with a 3000-kg car traveling at 60.0 km/h south. The two cars stick together after the collision. (See Fig. 7-1.) What is the speed of the cars afx4kx9vq5 uize y41 aniba7ep 6(4if vd (c*/ufter 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 3000-kg car tragj0*j megq*y/honb4)xruqbh ( pg 9; 3veling at 60.0 km/h south. The two cars stick together after the collision. (See Fig. 7-1.) What is the direction of motion of the n qebhyqgopu xr**;mh) 0jgjg 3b(/94 cars after collision?

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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 , ,8j i:8vfbi 8xrmqfxfrictionless surface. 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. W,8x ibrj 8v: xmfi8fq,hat 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 velo0 7ehv u*+en*-kryluecity of 4.0 m/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; an e0*ne7kh*y+l -vr ueud a third fragment with a mass of 1.0 kg. What is the velocity of the third 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 sits(v; 6 knygysj5fp42qo at x = + 21.0 m. Where is the center s ;(yjvq24g65 ofpnkyof 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 two-particle system is at the origin. One parti rz9wjj mt. t49* a8m(i*jre5lhu9nmfcle is located at (3.0 m, 0) and has a mass of 2.0 kg. What is the location of the second mass of 3.0 kt r zw8*jm 459je mm9j*tf.r9alun ih(g?

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 a .i65 fd:reg5api.st et (0, 0), 2.0 kg at (2.0, 0), and 4.0 kg at (2.0, 1.0). Determine the coordinates of the center prd f i6gta.:5e5ei .sof 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 kg, 2.0 kg, and 3.0 kg, are located at (0, 0), (ka4ld+jlbc-7 r z.h -v1.0 m, 1.0 m), and (2.0 m, -2.0 m), respectively. What is the location of the center of mass of theaj lb-+ -r7hv4.clz kd system?

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 positioned at (0, 8.0), ;mn dytn34k05mgp2ifdwla963 ev p2f and a 1.0-kg mass is positioned at (12, 0). What arm fp4 yg3 t;apfn59n622lwdkmi 0e3v de 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, (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 whole leggi60wm;bo l2 jj *85+onqbda u5vd8c l including the foot when the leg is stretched straight out. Assume the person o *nb +8cjidwm;j6v5gbl2uol da 085q 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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