What did physicist James Joule's famous paddle wheel experiment demonstrate?

A. that the initial gravitational potential energy of the masses transformed into kinetic energy of the paddles and then to thermal energy in the water

B. that the kinetic energy of the turning paddles increased the gravitational potential energy of the masses

C. that the thermal energy of the water could be transformed into kinetic energy of the turning paddles

D. that falling masses to turn paddles is a practical way to warm water for household use

Answer

A. that the initial gravitational potential energy of the masses transformed into kinetic energy of the paddles and then to thermal energy in the water

Explanation

James Joule allowed some water to fall from a height of 1 foot. the water would turn a paddle wheel at the bottom causing a temperature of water to raise.

The height form which the water fell, mass and the temperature of water was measured and used to calculate mechanical equivalent of heat.

From the choices given the best answer is A. that the initial gravitational potential energy of the masses transformed into kinetic energy of the paddles and then to thermal energy in the water.

that the initial gravitational potential energy of the masses transformed into kinetic energy of the paddles and then to thermal energy in the water

Explanation:

Joule was one of the foremost scientists to opine that one form of energy could be converted into other forms. In the famous "paddle wheel" experiment he used a falling weight to pull a string that turned a paddle wheel submerged in a bucket of water. It was discovered that the mechanical energy released by the falling weight was converted into heat energy by the paddle wheel. Joule then measured the amount of heat energy absorbed by the water by recording the temperature of the water before and after the paddle wheel began moving. He discovered that the increase in water temperature was directly related to the amount of kinetic energy released.