(a) A body thrown in the vertically upward direction rises up to a height 'h' and comes back to the position of rest. Calculate the displacement of the body.
(b) A body starts to slide over a horizontal surface with an initial velocity of `0.5 m s^(-1).` Due to friction, its velocity decreases at the rate of 0.05 `ms^(-2).` How much time will it take for the body to stop ?

Explanation

(a) The displacemenet of the body isd zero. Because the initial starting position and the final positon are the same.
(b) Her, `u = 0.5 ms ^(-1) ,v =0, a =- 0.05 ms ^(-2)`
`(because` the velocity decreases), t = ?
` v = u + at`
`therefore 0 =0.5 ms ^(-1) + (-0.05 ms ^(-2)) xx t `
`therefore 0.05 ms ^(-2) xx t =0.5 ms ^(-1)`
`therefore t = (0.5 ms ^(-1))/(0.05 ms ^(-2))= 10 s `
The body will stop after 10 second.