Airplanes vs. Rockets:

Airplanes vs. Rockets:

What are the principles of flight for planes and

rockets?

Principles of flight: airplanes

• What causes airplanes to fly?

Principles of flight: airplanes

• What causes airplanes to fly?

• Bernoulli’s Principle:

Principles of flight: airplanes

• What causes airplanes to fly?

• Bernoulli’s Principle: As the speed of a moving fluid increases, the pressure within the fluid decreases.

Principles of flight: airplanes

• What causes airplanes to fly?

• Bernoulli’s Principle: As the speed of a moving fluid increases, the pressure within the fluid decreases.– Faster flowing air has less pressure so an

object will be pushed in the direction of the fast moving air by the normal air pressure on the other side.

Principles of flight: airplanes

• Why does the air speed change?

Direction of travel for the plane

Principles of flight: airplanes

• Why does the air pressure change?

Principles of flight: airplanes

• Why does the air plane go up?

Principles of flight: Rockets

• Rockets do not use Bernoulli’s principle for take off.

Principles of flight: Rockets

• Rockets do not use Bernoulli’s principle for take off.

• Instead they utilize Newton’s Third Law.

Principles of flight: Rockets

• Rockets do not use Bernoulli’s principle for take off.

• Instead they utilize Newton’s Third Law.– Newton’s Third Law states that every action

has an equal and opposite reaction.

Principles of flight: Rockets

Principles of flight: Rockets

Principles of flight: Rockets in orbit

• What needs to happen to achieve orbit?

Principles of flight: Rockets in orbit

• What needs to happen to achieve orbit?

• To achieve and maintain an orbit there needs to be a balance between the force of gravity between the two objects and the orbiting object’s inertia.

Principles of flight: Rockets in orbit

• What needs to happen to achieve orbit?– Inertia (Newton’s 1st law): States that an

object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an outside force.

Principles of flight: Rockets in orbit

• What needs to happen to achieve orbit?– Inertia (Newton’s 1st law): States that an

object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an outside force.

– Increasing speed increases inertia.

Speed of rocket

Speed of rocket

Gravity

Speed of rocket

Gravity

If speed equals gravity you are in a constant orbit.

Speed of rocket

Speed of rocket

Gravity

Speed of rocket

GravityIf speed is less than Gravity you are in a

decaying orbit (crashing or landing).

Speed of rocket

Speed of rocket

Gravity

Speed of rocket

GravityIf speed is more than gravity you are leaving orbit (going

to the moon).