If v1 be the velocity at the time of projection and v2 be the velocity at height 25 m , then v22=v12−2g×25 If t be the time taken to reach at maximum height H from point B, then 0=v2−gt v2=gt=10×2=20m∕s ∴ From eq. (i), 202=v12−2×10×25 ⇒400+500=v12 ⇒v1=√900=30m∕s
