Answer
The ball's velocity when it loses contact with the player's foot is $~~20~m/s$
Work Step by Step
In part (a), we found that the impulse on the ball from the foot is $~~9.0~kg~m/s$
The ball's momentum when it leaves the foot will be equal to this impulse.
We can find the ball's velocity:
$p = 9.0~kg~m/s$
$m~v = 9.0~kg~m/s$
$v = \frac{9.0~kg~m/s}{m}$
$v = \frac{9.0~kg~m/s}{0.45~kg}$
$v = 20~m/s$
The ball's velocity when it loses contact with the player's foot is $~~20~m/s$.
