Question

A ball is projected vertically down with an initial velocity at a height of 20m

Answer 1

Hello!

Here is your answer

Given

height = 20m

initial velocity = ?

$v { }^{2} - u {}^{2} = 2gh$
so,

$0 {}^{2} - u {}^{2} = 2 \times 10 \times 20$
$- u {}^{2} = 400$
$u = - 20$