APPLICATION OF FAMOUS PRINCIPLES IN THE WORKING OF ROCKETS

A rocket consists of an engine, fuel, oxidizers, propellant tanks, etc. The propellants (the fuel and the oxidizer) undergo combustion at high temperatures and high pressures. Combustion produces gases, which escape at high velocities to produce a force, which is thrust. This process enables the rocket to go upwards in space at high velocities. Continue reading this blog to learn about the application of the famous principles in the working of rockets.

APPLICATION OF FAMOUS PRINCIPLES IN THE WORKING OF ROCKETS

NEWTON’S FIRST LAW OF MOTION

Newton’s first law of motion states that an object at rest tends to stay at rest, and an object in motion tends to remain in motion at a constant speed in a straight line unless it is subjected to an outside force.

First, let us understand what the balanced forces are. A ball is at rest if it is kept on the ground. It means that balanced forces are acting on it. A ball is in motion while it is rolling. A ball in motion changes its position as per its surroundings. As per Newton’s first law, motion means the changing position of an object as per its surroundings.

Then, let us understand what the unbalanced forces are. If a person holds a ball in his/her hand and keeps it still, it means that the ball is at rest. The time until the ball is held in the hand, few forces act on it. The gravitational force tries to send the ball downwards. At that time, the hand holding the ball is indirectly pushing the ball to keep it held up. Thus, we can say that the forces acting on the ball are being balanced. When the person leaves the ball or brings the ball up, then the forces become unbalanced. Then, the state of the ball changes from the state of rest to the state of motion.

This is Newton’s first law applied to a ball.

HOW DO WE APPLY NEWTON’S FIRST LAW ON ROCKETS

We will understand this concept of Newton’s first law mentioned above regarding rockets. For rockets in flight, the forces become balanced and unbalanced all the time. A rocket that is there on the rocket launch pad is balanced. When the engines of the rocket are ignited from the burning of the combustion products, the exhaust gases come out, which help in the rocket propulsion upwards, as mentioned in this article about the principle of a rocket engine.

The gravitational force on the rocket tries to send it downwards. This creates an unbalance of forces acting on the rocket, which becomes balanced and the rocket goes upwards in space. The velocity produced to send the rocket upwards must be large enough. Afterward, when the rocket runs out of fuel, it goes slowly. Then, it stops at the highest point of the flight, and it falls back to the Earth.

NEWTON’S SECOND LAW OF MOTION

Newton’s second law of motion states that the acceleration of an object is directly proportional to the force applied to it and inversely proportional to its mass. The force on an object is the product of its mass and acceleration.

F=m*a

HOW DO WE APPLY NEWTON’S SECOND LAW FOR ROCKETS

Accelerations of objects vary according to their masses. The pressure created from the controlled explosion taking place in the engine of a rocket is called thrust. It is a force. This pressure helps accelerate the gases to go downwards, and thus the rocket to go upwards. The thrust of the rocket keeps continuing as long as the engines keep on firing. The mass of the rocket varies while it is in flight. The largest part of the rocket’s mass is its propellants, which constantly vary as the engine fires. It means that the mass of the rocket gets smaller during flight. That is why the acceleration of the rocket increases as its mass decreases. This is the reason why a rocket begins moving slowly, then it goes faster and faster as it climbs up into space.

For a rocket to climb into the low Earth orbit, it is required to achieve a speed of more than 28,000 km per hour. The escape velocity required for a rocket to leave Earth and travel into space is about more than 40,250 km per hour. The engine of a rocket should burn a large amount of fuel, and send the resultant gases out as quickly as possible.

Thus, Newton’s second law can be explained for a rocket. The more the mass of the fuel of the rocket burnt, and the faster the gases produced can escape the engine, the greater the thrust of the rocket.

NEWTON’S THIRD LAW OF MOTION

Newton’s third law of motion states that, when two objects interact with each other, they apply forces on each other, of equal magnitude and opposite in direction. For every action, there is an equal and opposite reaction. A rocket can launch from its Launchpad only when it has sent all of its gases out of its engine. The rocket pushes on the gases, and then the gases push on the rocket.

HOW DO WE APPLY NEWTON’S THIRD LAW ON ROCKETS

As we know, every action has an equal and opposite reaction. Action in rockets as per the application of Newton’s third law of motion, is the escape of the gases out of the engine. The reaction is the movement of the rocket in the upward direction. To enable a rocket to go upwards by lifting off from the Launchpad, the force of the gases going out from the engine must be greater than the mass of the rocket. This will move the rocket upwards in space.

THE APPLICATION OF THREE NEWTON'S LAWS ON ROCKETS

As per Newton’s first law of motion, for a rocket to get lifted from the launch pad, a force must be applied to change the velocity or direction. As per Newton’s second law of motion, the amount of the force produced by the rocket engine is found from the mass of the fuel burnt from combustion, and the velocity with which the gases escape out from the rocket. As per Newton’s third law of motion, the reaction or motion of the rocket is equal and in the opposite direction of the action, or thrust from the engine.

CONCLUSION

This blog provides you a complete understanding about the application of famous principles in the working of rockets. Read this blog to learn about the working principle of a rocket engine. Continue visiting our website for more information about rockets.