A twig from a tree drops from a 200m high cliff on to a beach below. during its fall 40% twig's energy is converted into thermal energy. what is the speed with which the twig hits the beach?

Calculating for potential energy P. E=mgh

m=mass

g=acceleration due to gravity

h=height

Let the twig's mass be M

therefore at the start, the twig has 200*9.8*M potential energy.

During its fall 40% twig's energy is converted into thermal energy and the remaining 60% of this will turn into kinetic energy during the fall, giving us 1176M

Now the equation for kinetic energy, K. E is 0.5*m*v^2

m is mass

v is velocity

Therefore 1176M=0.5*M*v^2 (mass will divide out)

velocity is 48.49 m/s