# Firing a boat

**Classical Mechanics**Level 2

A boat is moving with a velocity \(v\) directly away from a gun located on the bank of a river.The gun fires a shell with a speed \(u\) at an angle\( \theta \) with the horizontal.If the shell hits the boat ,then the distance of the boat from the gun at instant the shell is fired is given by \[s=\frac{1}{g} \times {au\sin\theta( u \cos\theta - v)} .\] What is the value of \(a\)?