Thrust
The ‘strength’ of a rocket engine is called its thrust. Thrust is the force which moves the rocket through the air and through space. Thrust is the force produced measures in pounds, kilograms or Newtons. Thrust made by the first stage must be greater than the weight of the complete launch vehicle while standing on the launch pad in order to get it moving. Once moving upward, thrust must continue to be produced to accelerate the launch vehicle against the force of the Earth’s gravity. Thrust is generated by the propulsion system of the rocket through Newton’s third law of motion; for every action there is an equal and opposite re-action. In the propulsion system, an engine works on a gas or liquid, called a working fluid. The re-action to the acceleration of the working fluid produces the thrust force on the engine. The working fluid is expelled from the engine in one direction and the thrust force is applied to the engine in the opposite direction.
All rocket engines produce thrust, by accelerating a working fluid. However, there are lots of ways for producing the acceleration and there are many different working fluids. The simplest rocket engine uses air as the working fluid and pressure produced in a pump to accelerate the air. This is the type of engine used in a toy balloon or a stomp rocket. A stomp rocket is a toy rocket and it is compressed by air. So when, someone stomps on the rocket, it shoots up like a real rocket.
All rocket engines produce thrust, by accelerating a working fluid. However, there are lots of ways for producing the acceleration and there are many different working fluids. The simplest rocket engine uses air as the working fluid and pressure produced in a pump to accelerate the air. This is the type of engine used in a toy balloon or a stomp rocket. A stomp rocket is a toy rocket and it is compressed by air. So when, someone stomps on the rocket, it shoots up like a real rocket.