A body of mass 10 kg is kept at a height of 5 m. It is allowed to fall and reach the ground.
What is the total mechanical energy possessed by the body at the height of 2 m assuming it is a frictionless medium ?

Explanation

The speed of body when at a height of 2m above the ground i.e. after falling through 3 m is :
`V^2 = U^2 + 2 gh = 0 +2 xx 10 xx 3`
` V= sqrt(60 ) ms^(-1)`
` therefore ` Mechanical energy at 2 m height `= P.E +K.E = mgh +1/2 mv^2 `
`= 10 xx 10 xx 2 + 1/2 xx 10 xx 60 = 500 J`