Respuesta :

DeanR

y = v₀t - gt²/2

For y=0 (back to where we started),

0 = t(v₀ - gt/2)

t=0 (which we knew) or v₀ - gt/2 = 0

v₀ = gt/2

2v₀ = gt

t = 2v₀/g

t = 2 (35.7 m/s) / (9.8 m/s/s) = 7.3 seconds

Answer: 7.3 seconds