A player throws a ball upwards with an initial speed of `30 m s^(-1)`. How long does the ball take to return to the player's hands? ( Take g = 10 `m s^(-2)`)

Options

A. 3 s
B. 6 s
C. 9 s
D. 12 s

Answer

B

Explanation

Let t be time taken by the ball to reach the highest point.
As v = u + at
Here, u = `30 m s^(-1)`
v = 0 (At highest point velocity is zero)
a = - g = `- 10 m s^(-2)`
`therefore`0 = 30 - 10t or t = 3 s
`therefore` Time taken by the ball to return to player's hand
= 3 s + 3 s = 6 s.