Question

A ball is thrown vertically upwards from ground,
when it is at 3/4th of its maximum height its speed
is 20 m/s. The speed of throw is
(1) 15 m/s
(2) 25 m/s
(3) 35 m/s
(4) 40 m/s​

Answer 1

Answer:

Explanation:

we only us. Hmax = u^2 /2g

now at 3/4 of Hmax means 1/4 the dist is remaining so we can use

1/4Hmax = 20^2 / 2g for 1/4 dist 20m/s is initial velocity so we can use this

Here comes Hmax = 80

NOW WE USE. 80 = u^2 / 2g and the answer is. 40m/s