In the friction cone experiment the hanging mass, which was `250g` remained stationary when the wheel was rotated at the rate of `1//2` revolutioin per second. Calculate Joule's mechanical equivalent of heat if the rise in temperature was `4^(@)C` in 15 minutes.The total water equivalent of cones and water was `100g`, diameter of the wooden disc `=50cm` sp. heat capacity of water `=1000cal` per kg per kelvin.

Answer

`4.33Jcal^(-1)`