Question

A cannon and a target are 5.10 km apart and located at the same level. How soon will the shell launched with the initial velocity 240 m/s reach the target in the absence of air drag?

Answer 1

$s=5.10 \space km=5100\space m$

$t=\frac{s}{v}=\frac{5100}{240}=21.25$ ($s$)