Question

A ball of mass 20 gram hits a wall at an angle of 45° with a velocity of 15 m/s .if the ball rebounds at 90° to the direction of incidence ; calculate impulse recieved by ball

Answer 1

Initial velocity = uCos45i + uSin45j
Final velocity = -uCos45i + uSin45j

Change in velocity = uCos45i + uSin45j - (-uCos45i + uSin45j)
= 2uCos45 i
= 2u/√2 i
= u√2 i
= 15√2 m/s (along horizontal towards wall)

Impulse = Change in momentum
= mass * Change in velocity
= 20*10^-3 kg * 15√2 m/s
= 0.42 kgm/s along

Impulse received by ball is 0.42 kgm/s

Answer 2

5×2^1/2

Explanation:

change in p =-mvcos45-mvcos45=-2mvcos45