A 40%-efficient car engine accelerates the 1300 kg car from rest to 20 m/s How much energy is transferred to the engine by burning gasoline? .

Answer 1

Calculate the kinetic energy increase and divide it by 0.4, to account for the inefficiency.

(1/2)M*V^2/0.4
= 6.5*10^5 Joules
That is the fuel energy burned. 60% of that goes to heating the engine, if the engine is 40% efficient.