**A ball is thrown vertically upwards with a velocity of 20ms ^{−1} from the top of a multistorey building. The height of the point where the ball is thrown 25 m from the ground. How long will it be before the ball hits the ground ? Take g=10ms^{−2}.**

**Answer:**

Initial velocity of the ball =

The time it will take to reach the maximum height:

The maximum height ball reached from building can be calculated by:

Maximum height from ground =

Time the ball will take from maximum height to reach ground:

So, the total time the ball will take to hit the ground =