Question

In a rocket fuel burns at the rate of 2kg/s.this fuel gets ejected from the rocket with a velocity of 80 km/s.force exerted on the rocket is

Answer 1

if
$f = ma$
the force exerted is =
$80 \times 2 = 160kmkgs { - }^{2}$

Answer 2

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

F = 1 × 60000 =60000 N

Therefore the force exerting on the rocket = 60000 N