1. The problem statement, all variables and given/known data Your 1500-kg car, moving at 7.0 m/s, approaches the bottom of a hill that is 20 m high (Figure 1) . To save gas, you use on average only 3.2kW of engine power, realizing that half of the energy delivered by the engine and half of the initial kinetic energy will be dissipated. If you calculated correctly, your car will just barely make it over the hill. What time interval is required for your car to travel from the bottom to the top of the hill? 2. Relevant equations KE=1/2mv^2 PE=mgh P=W/T y=v0t+.5at^2 3. The attempt at a solution KE=.5(1500)(7)^2 =36700 Joules or 36.75 kJ P=W/T 3.2 KW=36.75 KJ/T T=11.48 Seconds IT SAYS I'M WRONG SO I DID THIS "half of the initial kinetic energy will be dissipated" 3.2=18.38/T T=5.74 IT STILL SAY I WRONG SO I DO THIS 20=7t+.5(9.8)t^s t=1.42 seconds (Used quadratic formula to solve for T). But then I think perhaps the car is accelerating I mean that's the only way it has power right? So the acceleration is not 9.8 but 9.8 plus something because the acceleration of the car has to overcome the acceleration due to gravity in order to make it over the hill. I tried substitution of the time in P=W/T into the y=v0t+.5at^2 equation in order to find the acceleration of the car but that's just a pain in the ass and you know what my graphing calculator told me? It told me the acceleration is 9.8 I kid you not. I can't get the right answer and I feel so dumb and I know I'm so dumb please help.