Question

A gymnast bounces vertically upward from a trampoline as shown in figuare the gymnastic leaves the trampoline at a height of 1.20 m and reaches a maximum height of 4.80 m before falling back down all heights are measured with respect of the ground

Answer 1

$$0.5mv^2=mg(H-h)\\v^2=2g(H-h)\\v^2=2(9.8)(4.8-1.2)\\v=8.4\frac{m}{s}$$