Question

In a waterfall, much of the energy of the falling water is converted into heat.

If all the mechanical energy is converted into heat that stays in the water, how much of a rise in temperature occurs in a 100 m waterfall? For water, c = 4.186 × 103 J/(kg • C°)

Answer 1

one kg water falls 100 meters

potential energy loss = m g H
= 1 * 9.81 * 100 = 981 Joules
so
981 Joules goes to heat that 1 kilogram

981 J = 1 kg * 4.186*10^3 * delta T
so
delta T = 981 /(4.186*10^3)