CP While painting the top of an antenna 225 m in height, a worker accidentally lets a 1.00-L water bottle fall from his lunchbox. The bottle lands in some bushes at ground level and does not break. If a quantity of heat equal to the magnitude of the change in mechanical energy of the water goes into the water, what is its increase in temperature?
Solution 32E Step 1: When the bottle is falling from 225 m height, only force acting on it will be gravitational force if air resistance is neglected. Therefore, distance travelled, S = 225 m Acceleration due to gravity, g = 9.8 m/s 2 Step 2: We know that, the potential energy of the bottle at a height, S is, U = mgS Where, m - mass of the body Provided, the volume of water, V = 1 litre Density of pure water, D = 1000 g/L From the equation for density, D = Mass/volume Therefore, Mass, M = D × V = 1000 g/L × 1 L = 1000 g = 1 kg