A 125-g arrow is shot vertically upward with an

initial speed of 28 m/s. Assuming 30% loss in total
mechanical energy while ascending, what maximum
height above the position from which it was shot does
the arrow reach?

1 answer

Ke at start = .5 (.125) 28^2
= 49 Joules
.7 * 49 = 34.3 Joules

= m g h = .125 * 9.81 * h
so
h = 28 meters