Question

4. A ball is thrown vertically upwards. It
reaches its maximum height in 2.5 s. If the
acceleration of the ball 10 m/s2 be directed
towards the ground, find the initial
velocity of the ball. (Ans. 25 m/s)​

Answer 1

t = 2.5s

a = -10m/s² {it is taken as negative cause the ball is going upwards in this question, against gravity}

v = 0m/s {cause at some time it's gonna reach the highest point where it is gonna be at rest}

By equation,

v = u+at

0= u -10×2.5

-u = -25

u = 25m/s

Cheers!