Question

A ball of mass 50 g moving at a speed of 2.0 m/s strikes a plane surface at an angle, it rebounds at an equal angle with the same speed. Calculate the change in the magnitude of momentum of the ball

Answer 1

0.1 is the answer. it may be correct or wrong

Answer 2

let ball is moving in x-y plane & approaching a wall at an angle x degree which is placed in y-z plane...
initial momentam of ball is Pi =mvcosx i + mvsinx (-j)
finally it returnes at same angle & with same velocity so its final momntam is
Pf = mvcos x(-i) + mvsinx (-j)
change in momentam= Pi - Pi =2mvcosx