Question

A stone after falling freely under the influence of gravity for 1 s strikes a glass pane held horizontally. In breaking through the glass pane, the stone loses half of its velocity. How far will it travel in next two seconds?

Answer 1

Velocity before hitting glass plate = gt =$10\times 1=10m/s$
As it loses half its velocity, vecocity when it comes out of glass =$\frac{10}{2}=5m/s$
Now, $s=ut+\frac{1}{2}g{t}^2=5\times 2+\frac{1}{2}\times 5\times 2^2$ = 10 + 10 = 20m