Question

A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of $5.0m{s}^{-2}$. Calculate the initial thrust (force) of the blast.

Answer 1

Mass of the rocket, m = 20,000 kg
Initial acceleration, $a=5m/s^2$
Acceleration due to gravity, $g=10m/s^2$
Using Newton’s second law of motion, the net force (thrust) acting on the rocket is given by the relation:
$F-mg=ma$
$F=m(g+a)$
$F=20000\times (10+5)=20000\times 15=3\times {10}^{5}N$.