Question

Robert applies a 27.95 N-s impulse to Rebecca while ice skating. If Rebecca, whose mass is 59.11 kg, left Robert's hands at 6.129 m/s after he pushed her, how fast was Rebecca moving before the push?

Answer 1

As per Impulse momentum theorem we know that

Impulse = final momentum - initial momentum

so now here we have

impulse = 27.95 N-s

mass = 59.11 kg

final speed = 6.129 m/s

now we have

`I = m(v_f - v_i)`

`27.95 = 59.11(6.129 - v_i)`

`0.473 = 6.129 - v_i`

`v_i = 6.129 - 0.473`

`v_i = 5.656 m/s`

so initial speed must be 5.656 m/s