એક બોલને શિરોલંબ ઉપર તરફ ફેંકવામાં આવે છે.

Let particle thrown with velocity $u$ and its maximum height is $H$ then $H = \frac{{{u^2}}}{{2g}}$

When particle is at a height $H/2$, then its speed is $10\, m/s$

From equation ${v^2} = {u^2} - 2gh$

${(10)^2} = {u^2} - 2g\left( {\frac{H}{2}} \right) = {u^2} - 2g\frac{{{u^2}}}{{4g}}$$ \Rightarrow {u^2} = 200$

Maximum height $ \Rightarrow H = \frac{{{u^2}}}{{2g}} = \frac{{200}}{{2 \times 10}} = 10\;m$