Question

A ball kicked horizontally at 10.0m/s from a cliff 80m high. How far from the base of the cliff will the stone strike the ground?

Answer 1

$h(t)=H-\frac{gt^2}{2}=80-4.9t^2$

$h(t)=0 \to 80-4.9t^2 \to t=\sqrt{\frac{80}{4.9}}=4.04 s.$

$S=vt=10*4.04=40.4m.$