The Physics in Rocket Ships

Conclusion

Why do they Work?

• The new rockets will not look like the space shuttle. These rockets will look more like earlier ones and will be tall and round and thin.
• They will take astronauts into space, as well as, supplies to the International Space Station.
• NASA also is working on a powerful new rocket called a heavy lift vehicle. This rocket will be able to take big loads into space.

• Together, these new rockets will make it possible to explore other worlds. Someday they may send humans to Mars.

• Rockets work by a scientific rule called Newton's third law of motion.
• English scientist Sir Isaac Newton listed three Laws of Motion. He did this more than 300 years ago.
• His third law says that for every action, there is an equal and opposite reaction.
• The rocket pushes on its exhaust. The exhaust pushes the rocket, too. The rocket pushes the exhaust backward. The exhaust makes the rocket move forward.

This rule can be seen on Earth. ex- a person is standing on a skateboard. Imagine that person throwing a bowling ball. The ball will go forward. The person on the skateboard will also move. The person will move backward. Because the person is heavier, the bowling ball will move farther.

How it Works

• Just as most engines, rockets burn fuel.
• Most rocket engines turn the fuel into hot gas.
• The engine pushes the gas out its back.
• The gas propels the rocket forward.

Resources

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0CDIQFjAD&url=https%3A%2F%2Fwww.boundless.com%2Fphysics%2Ftextbooks%2Fboundless-physics-textbook%2Flinear-momentum-and-collisions-7%2Frocket-propulsion-71%2Frocket-propulsion-changing-mass-and-momentum-302-11258%2F&ei=LdtnVcncNuPksATki4CQBw&usg=AFQjCNEXOzm0-uV-Zp_1b5mmYAg8XYMGbQ&bvm=bv.93990622,d.cWc

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CDkQFjAE&url=http%3A%2F%2Fffden-2.phys.uaf.edu%2F211.fall2000.web.projects%2FI.%2520Brewster%2Fphysics.html&ei=LdtnVcncNuPksATki4CQBw&usg=AFQjCNGQop71J5TepwIXSYszwUVCADuYIA&bvm=bv.93990622,d.cWc

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&cad=rja&uact=8&ved=0CEwQFjAH&url=http%3A%2F%2Fscience.howstuffworks.com%2Frocket1.htm&ei=LdtnVcncNuPksATki4CQBw&usg=AFQjCNGJSN6j8Azv6o6UDgcT_ZZJ6wEguw&bvm=bv.93990622,d.cWc

Why it works

• Rockets have variable mass because its mass decreases over time, as a result of its fuel/propellant burning off.

What are Rockets?

• Most people think of a tall, thin, round vehicle that launches into space.

• A rocket obtains thrust by the principle of action and reaction (Newton's third law).
• As the rocket propellant ignites, it experiences a very large acceleration and exits the back of the rocket (as exhaust) at a very high velocity.
• This backwards acceleration of the exhaust exerts a "push" force on the rocket in the opposite direction, causing the rocket to accelerate forward.
• This is the essential principle behind the physics of rockets, and how rockets work.

m is the mass of the rocket (including propellant), at stage (1)

me is the total mass of the rocket exhaust (that has already exited the rocket), at stage (1)

v is the velocity of the rocket, at stage (1)

Je is the linear momentum of the rocket exhaust (that has already exited the rocket), at stage (1). This remains constant between (1) and (2)

dme is the mass of rocket propellant that has exited the rocket (in the form of exhaust), between (1) and (2)

dv is the change in velocity of the rocket, between (1) and (2)

ve is the velocity of the exhaust exiting the rocket, at stage (2)

• Rockets are now usually used for fireworks, weaponry, ejection seats, launch vehicles for artificial satellites, human spaceflight, and space exploration.
• Chemical rockets are the most common type of high power rocket, typically creating a high speed exhaust by the combustion of fuel with an oxidizer.

Between rockets (1) and (2), the change in linear momentum in the vertical direction of all the particles in the system, is because of the sum of the external forces in the vertical direction acting on all the particles in the system.

The Physics in Rocket Ships

expressed mathematically using Calculus and the principle of impulse and momentum

By Ishani Vyas