A ball thrown up vertically returns to the thrower after 6 s. Find Velocity with which it was thrown up.

Explanation

Acceleration due to gravity, `g = -9.8 ms^(-2)`
Time t = 3 s (since the time to go up and return is 6s. `therefore` The time to go up = 3s)
Find velocity , `V = 0. ms^(-1)`
Initial velocity , u = ?
By first equation of motion,
`V = u + g t`
`rArr 0 ms^(-1) = u + (-9.8 ms^(-2)) xx 3s`
`rArr 0 ms^(-1) = u - 29.4 ms^(-1)`
`rArr u = 29.4 ms^(-1)`
The velocity with which it was thrown up = `29.4 ms^(-1)`.
Distance , s = Height, h = ?