You try to recreate James Joules experiment that demonstrate

You try to recreate James Joule\'s experiment that demonstrated the energy equivalence of heat and work, by dropping a weight of 5kg a height of lm, which causes a set of brass paddles to stir a 1-liter container of water (mass 1 kg) (see diagram). How much should the temperature of the water increase?

Solution

change in PE of the mass = mgh = 5*9.8*1 = 49 J

This energy is delivered to the water as heat by rotating the brass pedal.

it is assumed that the entired energy is converted to heat and is utilised by water no heat loss to the externel environment.

Specific heat of water = 4186 J/kg-k

mass of water in the container = 1 kg

rasie in temperature = 49/4186 = 0.012 deg-k