Question

A ball of mass 0.5kg moving with a speed of 10m/s rebounds after striking normally a perfect elastic wall.find the change in momentum of the ball.if contact time with the wall is 0.1 s.what force is exerted by the wall

Answer 1

mass of ball = 0.5 kg

initial speed = 10 m/s

final speed = -10 m/s ( because it rebounds elastically)

Change in momentum= mv - mu

=> ∆P = 0.5×(-10) - 0.5×10

=>∆P = -10 kg.m/s


Given that contact time = 0.1s

force = ∆P/t = -10/0.1 = -100 N

Thus, the change in momentum is 10 kg.m/s in the opposite direction of its motion and force acted is 100N in the opposite direction of motion.

Answer 2

⛦Hᴇʀᴇ Is Yoᴜʀ Aɴsᴡᴇʀ⚑
▬▬▬▬▬▬▬▬▬▬▬▬☟

➧ m = 0.5 kg
➧ u = 10 m/s
➧ v = -10 m/s

➧ Initial momentum = m
➾ u = 0.5 x 10
➾ 5 kg m/s

➧ Final momentum = mv
➾ 0.5 x (-10)
➾ -5 kg m/s

➧ Change in momentum = mv - mu
➾ -5-5
➾ -10 kg m/s ...✔

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Thanks...✊