Question

a ball is dropped from height of 20 m . velocity increases uni formally at the rate of 10m-2,with whay velocity it will strike the gound and what will be the time?
pls ............. answer 

Answer 1

it is a free fall motion with acclereation due to gravity a=10m/$s^{2}$
from laws of motion
v=u+at
s=ut+(1/2a$t^{2}$
but u=initial velocity=0
20=1/2*10*$t^{2}$
$t^{2}$=4
t=2 seconds
final velocity v=10*2=20m/s

Answer 2

See the attachment it'll help!!