We know that when an object is raised to a height it attains potential energy and when it is dropped from there the energy is converted into kinetic energy. When the object reaches ground it has no potential energy as its height is 0 and it also does not has any kinetic energy as its velocity is 0. WHERE DOES THE ENERGY GOES!!!!!!!????!!!!!!!

							
Dear Anupam
initially suppose we give velocity v to the object and we assume ground as base that is zero potential energy. then its total energy is 1/2 mv2 and when it reaches its max height h and stops for a moment then its potential energy is mgh. this will be equal to the 1/2 mv2 if there is no non conservative force like friction or air drag. gravitational force is conservative. suppose there is only conservative force that is gravitation then mgh=1/2 mv2
sum of P E and KE will be same throughout its motion. when it returns to ground there is a collision between ground and object. its depend on the type of collision , ground surface characteristics, friction etc. if everything is smooth and elastic collision is there then it will again gain the same velocity v. but in real life this is not the case. object will loose its energy and this enrgy will be given to the ground and gradually the object comes to rest after giving all its energy to the ground.
 
All the best.                                                           
AKASH GOYAL
AskiitiansExpert-IIT Delhi
 
Please feel free to post as many doubts on our discussion forum as you can. We are all IITians and here to help you in your IIT JEE preparation.
Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.
Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively :Click here to download the toolbar..