Question

an object is dropped from a height of 10m from the ground level.if the energy of the object reduces by 40% after striking the ground the height through which the object will bounce back is

Answer 1

let mass be x
then K.E=100x (K.E=m*g*h)
40%of energy is lost
so remaining energy=
100-40=60%

thus
60%of K.E=K.E2
60/100*100x=x*10*h
60=10h
therefore
h=6m