Question

an object thrown vertically upwards reaches a height of 500 metre what was its initial velocity how long will the objective to come back to the earth assume G is equal to 10 metre per second square

Answer 1

I guess object thrown vertically cuts are and pass higer than other

Answer 2

$maximum \: height = u{2} \div 2g$
where, u=initial velocity
g=acceleration due to gravity

$500 = u {2} \div 20$
$u {2} = 500 \times 20 = 10000 \\ u = \sqrt{10000} = 100$
$time \: of \: flight = 2u \div g$

$t = (2 \times 100) \div 10 = 20$