An elastic ball is dropped from a height of 100 m. Due to the earth,`20%` of the energy is lost. To what height the ball will rise ?

Explanation

After rebound the energy possessed by the ball =(80/100)xxmgh=80/100xxmgxx100
(because the ball loses`20%` of its energy after collision with each)If the ball after collision rises to height h then mgh=`80//100xxmgxx100 `therefore h=80m