1. The problem statement, all variables and given/known data A cyclist coasts down a 7.2 degree hill at a steady speed of 10 km/h. If the total mass of the bike and rider is 75 kg, what power output must the rider have to climb the hill at the same speed? 2. Relevant equations Power = Energy/Time Ek = 1/2mv^2 where m is the mass v is the velocity and Ek is the kinetic energy Eg = mgh where m is the mass g is a constant value of 9.8 h is the height above the ground and Eg is the gravitational potential energy. 3. The attempt at a solution Power = Energy/Time = (Ek + Eg)/Time = [1/2(75)(2.777)^2 + (75)(9.8)(2.7sin7.2)]/1 = 522 Watts Apparently the answer is 511 Watts. Can someone please tell me where i went wrong?