Question

Q. 13 What is the velocity of an object dropped from a height 'h'
having a mass ‘m' just before reaching the surface​

Answer 1

Answer:

When the body strikes the ground all its potential energy is converted to kinetic energy. Therefore it’s kinetic energy will be:

MgH

It’s velocity can be found from:

1/2*mv^2 =mgH

Hence v = sqrt(2gH)

The velocity can also be calculated from the constant acceleration kinematic formulas.

v =sqrt(2as)

And here a =g and s =H, leading of course to the same result.

Answer 2

Initial Energy of the body =K.E+P.E

KE i =0,PEi =mgh

Final Energy KEf +PEf

PE f =0

Energy is conserved

Final Energy = Initial Energy

KE f =PEi =mgh