Answer
(a) $U_0 = 2.16~J$
(b) The 25-g pebble could go up to a height of 8.8 meters.
(c) We ignored air resistance in solving this question.
Work Step by Step
The initial potential energy stored in the slingshot will be equal to the potential energy of the pebble at maximum height.
(a) $U_0 = mgh = (0.010~kg)(9.80~m/s^2)(22.0~m)$
$U_0 = 2.16~J$
(b) $mgh = U_0$
$h = \frac{U_0}{mg} = \frac{2.16~J}{(0.025~kg)(9.80~m/s^2)}$
$h = 8.8~m$
The 25-g pebble could go up to a height of 8.8 meters.
(c) We ignored air resistance in solving this question.