Question

if the energy of a ball falling from a height of 10metres is reduced by 40percent how high will it rebond ans should be 6m

Answer 1

Height from which ball is dropped,
Let the mass of the ball be M
h=10m,
Acceleration due to gravity,g=10 m/s^2
=)Energy in the ball=mgh=100 MJ
=)Energy reduced after striking the ground=100 M-40% of 100M=60 MJ
⇒ Energy reduced after striking the ground = 100M - (40/100) (1000M)
⇒ Energy reduced after striking the ground = 100 M - 40 M 60M J 
⇒ Height to which ball will go = Energy/mg =60M/10M = 6m

Answer 2

Explanation:

$\orange{\underline{\huge{\bold{\textit{\green{\bf{ANSWER}}}}}}}$

Height from which ball is dropped,

Let the mass of the ball be M

h=10m,

Acceleration due to gravity,g=10 m/s^2

=)Energy in the ball=mgh=100 MJ

=)Energy reduced after striking the ground=100 M-40% of 100M=60 MJ

⇒ Energy reduced after striking the ground = 100M - (40/100) (1000M)

⇒ Energy reduced after striking the ground = 100 M - 40 M 60M J 

⇒ Height to which ball will go = Energy/mg =60M/10M = 6m