A particle is relased from a height 20 m from the ground . After how much time and with what speed the particle hits time and with what speed the particle hits the ground ?
` [ "Take ": g=10 m* s^(-2)]`

Explanation

initial velocity ,`u=0` . Let the particle hit the ground after time t.
` therefore h= (1)/( 2) gt ^(2)`
`or , t^(2) = ( 2h ) /( g) = ( 2xx20 ) / (10) = 4 `
`or m t=2 s`
hence the particle hits the ground with a speed
` v=g t = 10 xx 2 =20 m* s ^(-1)`