Question

A small sphere of mass m kg = 2 moving with a velocity u i j m s = − 4 7 / collides with a smooth wall and returns with a velocity v i j m s = − + 3 / . The magnitude of the impulse received by the ball is

Answer 1

here, we have to use formula,

impulse = change in momentum

impulse = Pf - Pi

impulse = m(Vf - Vi)

here, m = 2 kg

Vf = (-i + 3j ) m/s

Vi = (4i - 7j) m/s

now,

impulse = 2 × ( -i + 3j - 4i + 7j)

= 2 × ( -5i + 10j)

=(-10i + 20j ) kg.m/s

hence, magnitude of impulse = √(10²+20²)

= 10√5 N.s