Question

a rocket starts initially from rest . its mass is 60kg and it has 600kg fuel. the fuel burns at a constant rate of 10kg/sec.and is ejected at a a speed of 1.6km/s. calculate the velocity acquired (i) 10 seconds and (ii) when the fuel is exhausted?

Answer 1

Answer:

Given the mass of fuel ejected per sec = 1 kg/s

Velocity with which the fuel is ejected,v = 60 km/s = 60000 m/s

Change in velocity(v-u)  = (60000 m/s -0) =60000 m/s

Force on the rocket,F = m a

begin mathsize 14px style straight F space equals fraction numerator straight m left parenthesis straight v minus straight u right parenthesis over denominator straight t end fraction straight F equals straight m over straight t cross times open parentheses straight v minus straight u close parentheses straight F equals mass space per space sec cross times change space in space velocity end style

F = 1×60000 =60000 N

Therefore the force exerting on the rocket = 60000 N

Explanation: