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

The correct option is A

0.7 kg/s

Force on the rocket $=\frac{udm}{dt}\therefore$ Rate of combustion of fuel $\left(\frac{dm}{dt}\right)=\frac{F}{u}=\frac{210}{300}=0.7kg/s$