A TV tower is 40 m high , A mass of 5kg is dropped from its top. calculate the potential energy at the top and kinetic energy just before it hits the ground .

according to law of conservation of energy

potential energy at top = kinetic energy at bottom

now,

potential energy at top, U = mgh

here,

m = mass = 5kg

g = acceleration due to gravity = 9.81m/s²

h = height = 40m

so,

U = 5 x 9.81 x 40

thus, we have

U = 1962 J

so,

kinetic energy at top, E = U = 1962J