Question

A 1000 kg rocket is fired from the ground so that exhaust speed is 400m/s. If rocket accelerates with 5metre per second square initially then fuel burning rate is

Answer 1

m₀ = mass of the rocket initially = 1000 kg

u = exhaust speed of the rocket = 400 m/s

a = acceleration of the rocket = 5 m/s²

dm/dt = rate of fuel burning

Thrust on the rocket is given as

F = u (dm/dt)

using newton's second law

F = m₀ a

combining the above two equations , we get

m₀ a = u (dm/dt)

inserting the values in the above equation

(1000) (5) = (400) (dm/dt)

dm/dt = 12.5 kg/s