From the top of a tower 100 m in height a ball is dropped and at the same time another ball is projected vertically upwards from the ground with a velocity of 25 m/s. Find when and where the two balls will meet? (g=9.8m/s)

Explanation

For the ball chapped from the top
`x=4.9t^(2)" " ...(i)`
For the ball thrown upwards
`100-x=25t-4.9t^(2)" " ...(ii)`
From eq. (i) & (ii),
`t=4s, x=78.4m`