Question & Answer

What principle of conservation do rockets work on ?
  (a){\text{ Conservation of mass}} \\
  (b){\text{ Conservation of energy}} \\
  (c){\text{ Conservation of linear momentum}} \\
  (d){\text{ none of these}} \\

ANSWER Verified Verified
Hint – When a rocket lifts up, burning fuel gases are ejected in a backwards direction which have both mass and velocity, providing momentum to the rocket to take off.

Complete step-by-step answer:
Rocket works on the principle of conservation of momentum. Rocket ejaculates gases in backward direction which creates momentum of the gases backwards and thus by conservation of momentum, the rocket gets momentum in the forward direction making it move forward.
Thus the rocket works on the principle of conservation of linear momentum.
Hence option (C) is correct.

Note – The propulsion of all rockets, jet engines, deflating balloons and even squids and octopuses is explained by the same physical principle that is Newton's third law of motion. Matter which is forcefully ejected from the rocket, produces an equal and opposite reaction.