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12. Objects A and B each have mass m. Each is traveling at speed v and in the op

ID: 1397106 • Letter: 1

Question

12.

Objects A and B each have mass m. Each is traveling at speed v and in the opposite direction from the other object. As explained by the law of conservation of momentum, which event could not occur after the two objects collide?

Both objects reverse direction, each traveling at v.

Both objects stick together, each motionless.

Both objects reverse direction, one traveling at 0.5v and the other at 2v.

Both objects reverse direction, each traveling at 0.5v.

13.

An ore cart of mass 1200 kg is rolling at a speed of 10.8m/s across a flat surface. A crane dumps ore into the cart from directly above it, after which the cart travels at 9.3 m/s. What mass of ore did the crane add to the cart? Assume that frictional forces with the flat surface are negligible.

240 kg

190 kg

110 kg

92 kg

14.

840 m/s

720 m/s

590 m/s

690 m/s

750 m/s

15.


A block of mass m = 4.8 kg slides from left to right across a frictionless surface with a speed Vi=7.3m/sIt collides with a block of mass M = 11.5 kg that is at rest. After the collision, the 4.8-kg block reverses direction, and its new speed is vf=2.5m/s. What is V, the speed of the 11.5-kg block?

6.5 m/s

4.1 m/s

5.6 m/s

4.7 m/s

3.7 m/s

12.

Objects A and B each have mass m. Each is traveling at speed v and in the opposite direction from the other object. As explained by the law of conservation of momentum, which event could not occur after the two objects collide?

Both objects reverse direction, each traveling at v.

Both objects stick together, each motionless.

Both objects reverse direction, one traveling at 0.5v and the other at 2v.

Both objects reverse direction, each traveling at 0.5v.

Explanation / Answer


12) since both bodies having the same mass and travelling with the same speeds

the event which doesnot occur is

Both objects reverse direction, one traveling at 0.5v and the other at 2v.

13)From law of conservation of momentum

(1200*10.8) = (1200+m)*9.3

1393.5 = 1200+m

m = 1393.5-1200 = 193.5 kg

So the answer is 190 kg

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14) apply conservation of momentum

(0.007*u)+(2.1*0) = (0.007+2.1)*V

apply law of conservation of energy


(0.007+2.1)*V^2 = (0.007+2.1)*9.81*0.4 = 8.26

V = sqrt(8.26/(0.007+2.1)) = 1.97 m/s

then (0.007*u)+(2.1*0) = (0.007+2.1)*V

0.007*u = (0.007+2.1)*1.97

u = 592.8 m/s

So answer is 590 m/s

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15) Apply law of conservation of momentum

(4.8*7.3)+(11.5*0) = (-4.8*2.5)+(11.5*V)

V = 4.1 m/s