Question

A building is on fire the fireman was at $5m$ distance from building and throwing water at speed of $10m/s$. Find the maximum height at which the water is thrown to stop the fire.

Answer 1

for horizontal direction,
$\begin{array}{c}V\cos \theta \times t=5\\ 10\cos \theta \times t=5\\ \cos \theta \times t=\frac{1}{2}\end{array}$
for vertical
$\begin{array}{c}H=\frac{v^2{\sin }^2\theta }{2g}\\ =\frac{{10}^2\times {\sin }^{2}15}{2\times 10}=1.25m\end{array}$

so, the maximum height at which the water is thrown to stop the fire is 1.25m