Question

If the force on a rocket moving with a velocity of 300 m/s is 210 N, then the rate of combustion of the fuel is

• A. 0.7 kg/s
• B. 1.4 kg/s
• C. 0.07 kg/s
• D. 10.7 kg/s

Answer 1

Answer: (A)

0.7 kg/s

Answer 2

Force on the rocket $= \frac{udm}{dt}$ ∴ Rate of combustion of fuel

$\left( \frac{dm}{dt} \right) = \frac{F}{u} = \frac{210}{300} = 0.7kg/s.$