The water kept in an earthen pot seeps into the small pores in the pot and evaporates from the surface of the pot. The heat required for evaporation is taken from water inside the pot, thus cooling the water stored inside. This is the reason why on hot summer days water remains cool in earthen pot.
Use Newton's second law F = mass * acceleration In your problem F = 500, and we know gravity is working on it so use a = 9.81 Substitute into the equation 500 = m * 9.81 m = 50.97 kg
