are such type of problems needed for jam...if yes then please provide its solution...

wilun Problem 5.5 A car weighing 1350 kg is going down a hill. When it is 60 m vertically above the bottom of the hill, the driver sees red light of traffic crossing at the bottom. His speed at the time brakes are applied is 20 ms. How much energy will be dissipated by the brakes if wind and other frictional effects are neglected. Take g 9.80 ms. Ans: 1323.5 kJ