Explain the principle of jet propulsion and further explain how this principle is applicable in jet engines and also in rockets.
Jet propulsion is motion produced by passing a jet of fluid (e.g. air or water) in the opposite direction to the direction of motion. By conservation of momentum, the moving body is propelled in the opposite direction to the jet.
A jet engine is a reaction engine that discharges a fast moving jet of fluid to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets and pump-jets. In general, most jet engines are internal combustion engines but non-combusting forms also exist.