A ball falls freely from rest and the total distance covered by it in the last second of its motion is equal to the distance covered by it in first five seconds of its motion. The total time of the stone when it is in motion would be

Options

A. Ratio of their times of flight is `4 : 5`
B. Ratio of their maximum heights is `9 : 16`
C. Ratio of their minimum speeds during flights is `4 : 3`
D. The bisector of the angle between their directions of projection makes `45^(@)` with horizontal

Answer

B, C, D

Explanation

Range `=(u^(2)sin 2theta)/(g)rArr 480=4900/980xxsin 2theta`
`(90-theta)` projection angle has sme range. ltbtgt time of flight :
`T_(1)=(2u sin theta)/(g), T_(2)=(2u sin(90-theta))/(g)`