what propels a rocket away from the surface of the earth?
A rocket is propelled away from the surface of the Earth using the principle of action and reaction known as Newton's Third Law of Motion. According to this law, for every action, there is an equal and opposite reaction. In the case of a rocket, the action is the expulsion of gas or exhaust gases at high speeds through the rocket engine, and the reaction is the resulting force that propels the rocket forward.
To explain how a rocket engine works, we first need to understand the concept of thrust. Thrust is the force that propels a rocket forward and is generated by the expulsion of gases at high speeds. As the exhaust gases are expelled from the rocket engine, they generate a backward force, known as exhaust velocity, due to the conservation of momentum. To balance this backward force and maintain equilibrium, an equal and opposite forward force, known as thrust, pushes the rocket forward.
The primary mechanism that produces thrust in a rocket engine is the combustion of propellant. Rockets usually use a combination of fuel and oxidizer, such as liquid hydrogen and liquid oxygen or solid propellants, to undergo a controlled chemical reaction known as combustion. This combustion generates an enormous amount of hot and high-pressure gases.
In a typical rocket engine, the propellant mixture is ignited, and the resulting gases are forced out of the rocket nozzle at high speeds. The nozzle serves to expand the gases and accelerate them even further. According to Newton's Third Law, as the exhaust gases are expelled backward, the rocket experiences an equal and opposite force in the forward direction, propelling it away from the Earth's surface.
So, in summary, a rocket engine propels a rocket away from the surface of the Earth by expelling high-speed exhaust gases, following Newton's Third Law of Motion.