Physics Question

Question

The engine, which has an efficiency of 50% and power of 10 kW, is powered by

diesel fuel. How long will the engine run with 800 grams of diesel remaining in the fuel tank?

Answer 1

You do not give the data for diesel fuel so I will get 20,020.2 Btu/gallon = 44,136.5 Btu/Kg

Using 1 KW = 3412 Btu/Hour implies 10 KW = 34,120 Btu/Hour

So, 34,120 Btu/Hour/44,136.5 Btu/Kg = .773 Kg/Hour or 773 grams/Hour

If there is 800 grams of fuel remaining, this translates into 1.035 hours of fuel

But since the efficiency is only 50%, the time left is .5 x 1.035 = .517 hours of running time.