A tennis ball of mass m = 0.08 kg and speed v=29 ms strikes a wall at a 45∘ angle and rebounds with the same speed at 45∘. What is the magnitude of the impulse given to the ball? Express your answer to two significant figures and include the appropriate units.

3.3 kg-m/s

Explanation:

The mass of the ball m = 0.08 kg

speed = 29 m/s

angle oat which its strikes the wall = 45°

Final speed of rebound = 29 m/s

angle of rebound = 45°

Momentum before collision = m cos ∅

==> 0.08 x 29 cos 45 = 1.64 kg-m/s

since the same variables are maintained in the rebound, then the momentum of rebound will be of the same magnitude, but in the opposite direction

= -1.64 kg-m/s

The impulse is the change of momentum =  -

= 1.64 - (-1.64 ) = 1.64  + 1.64  = 3.3 kg-m/s

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