An experimental model rocket has a mass of 0.054kg. The fuel that was used in one test had 215J of chemical potential energy. When the rocket reached an altitude of 119m, it was travelling at 48m/s and still rising. With what efficiency did the rocket convert chemical potential energy into mechanical energy.

Answer 1

total useful energy=mg*119+1/2 m 48^2

chem energy=215J

efficiency=useful energy/total chem energy

Answer 2

Eg = 0.045 X 9.81X119 = 62.9 Joul
Ek= 1/2 m v^2 = .5 X 0.054 x 48^2 = 62.2 Joul
ETotal = 62.9 + 62.2 = 125.1 J
Efficiency = 125.1 / 215 = 58 %

Answer 3

Eg = 0.045 X 9.81X119 = 62.9 Joul
Ek= 1/2 m v^2 = .5 X 0.054 x 48^2 = 62.2 Joul
ETotal = 62.9 + 62.2 = 125.1 J
Efficiency = 125.1 / 215 = 58 %