Question

A ball of mass 200 g falls from a height of 5 m. When it just reaches the ground, its KE is ____ J (g = 10 m/s2).

Answer 1

mass of the ball=200g=0.2kg

height=5m

potential energy=mgh

=0.2x5.10
=10J

potential energy=kinetic energy

kinetic energy=10 Joules

hope it helps...

Answer 2

when body released from 5m height then body initial velocity=0
now use
v^2=u^2+2as
=0 +2 (-10)(-5)=100
now
kinetic energy=1/2mv^2
=1/2 x (200/1000) x 100
=10 j