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## At the county fair, Chris throws a 0.12kg baseball at a 2.4kg wooden milk bottle, hoping to knock it off its stand and win a prize. The ball

Question

At the county fair, Chris throws a 0.12kg baseball at a 2.4kg wooden milk bottle, hoping to knock it off its stand and win a prize. The ball bounces straight back at 30% of its incoming speed, knocking the bottle straight forward.

What is the bottle’s speed, as a percentage of the ball’s incoming speed?

Express your answer using two significant figures.

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Physics
5 months
2021-08-13T22:37:31+00:00
2021-08-13T22:37:31+00:00 2 Answers
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## Answers ( )

Answer:=6.5%

Explanation:Mass of the ball: ]

Initial velocity of the ball:

final velocity of the ball: which is -30/100 of =

Mass of the bottle:

Initial velocity of the bottle:

final velocity of the bottle: is unknown (to find)

by using conservation momentum, which stated that the initial momentum is equal to the final momentum.so since the bottle is at rest firstly, thereforeequation 1so now substitute into equation 1

collect the like termsdivide both side by

Now substitute

6.5%

Answer:

v2 = 6.5% of the ball’s initial velocity

Explanation:

Let the mass of the ball and bottle be m1 and m2 respectively.

m1 = 0.12kg , m2 = 2.4kg

Let the initial and final velocity of ball be u1 and

v1 = -0.3u1 while that of the bottle be u2 and v2

The bottle was initially at rest so u2 = 0m/s

From the principle of conservation of momentum, momentum before collision is equal to momentum after collision.

m1u1 + m2u2 = m1v1 + m2v2

0.12u1 + m2×0 = 0.12(–0.3u1) + 2.4v2

0.12u1 = –0.036u1 + 2.4v2

Collecting like terms

2.4v2 = 0.12u1 + 0.036u1

2.4v2 = 0.156u1

v2 = 0.156u1/2.4

v2 = 0.065u1 = 6.5%u1