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# IP Unit 4

### physics of motion in flight

Question | Answer |
---|---|

Stored energy due to height and gravity | Potential Energy |

The energy of motion | Kinetic Energy |

State the Law of the Conservation of Energy | Energy cannot be created or destroyed; it only changes form |

The distance something travels per unit time | Speed |

Speed in a given direction | Velocity |

What type of quantity is velocity? Scalar or vector? | A vector quantity |

What makes velocity a vector quantity? | Vectors have both magnitude (size) and direction (e.g. 35mph west) |

These have both magnitude (size) and direction (e.g. 35 mph west) | Vectors |

The highest speed that can be reached by a falling object is its __________ | terminal velocity |

Terminal velocity is achieved when ____ | the force of gravity (pulling down on the object) is cancelled by the force of drag (air resistance pushing upward) |

What happens as a plane climbs? | Its speed decreases as kinetic energy (motion) is converted into potential energy (position). |

What happens as a plane dives? | Its speed increases as potential energy (position) is converted into kinetic energy (motion). |

What is force? | A push or a pull on an object |

What two things does a vector quantity have? | Magnitude and direction |

What are the 4 forces of flight, and in which direction do they act? | Lift pushes upward, weight (the force of gravity) pulls downward, thrust moves the plane forward, and drag resists it. |

What do we call the force every object in the universe exerts on every other object? | The Force of Gravity |

What is the acceleration of gravity on Earth for every object, not matter what it's size. | 9.8 m/sec^2. All things, big and small, fall at this rate if there is not air resistance! |

Why is the gravity of the earth noticeable, but not other objects like you or your pencil. | Gravity depends on mass and distance. The closer two things are the more gravitational force, and the bigger the more gravitational force. The earth is way more massive that us! |

The force of gravity on the mass of an object gives us its ________. | Weight |

What is the force that helps pilots overcome the weight of the plane? | Lift |

What is the direction of lift? | Lift is "up." Its force is perpendicular to the plane in level flight in the opposite direction of weight. |

"As airspeed increases, the pressure drops" is an example of what principle? | The Bernoulli principle |

According to the Bernoulli principle, where is the pressure highest on a plane's wing? | The pressure is highest under the wing because the air is traveling slower. |

According to the Bernoulli principle, what creates lift? | The pressure above the wing is lower than the pressure below the wing (because air moves faster on top to cover a bigger distance), causing a net force upward (lift). |

What is net force? | The sum of all the forces exerted on an object. |

State Newton's 1st Law of Motion | An object in motion will remain in motion, and an object at rest will remain at rest, unless acted on by an unbalanced force. OR If the forces are balanced, the object stays moving at a constant speed or stays stopped. |

What is inertia? | The tendency of an object to resist a change in motion |

Objects with more ___ have more inertia. | mass |

State Newton's 2nd Law of Motion | An unbalanced force will produce a proportional acceleration. (That is, if an unbalanced force acts on an object, it will accelerate) |

What is sometimes stated as "for every action there is an equal and opposite reaction? | Newton's 3rd Law of Motion |

In a jet plane what are the action/reaction forces? | The engine pushes exploding gases backwards, and the gases push the plane forwards (thrust). |

When a propeller plane takes off, what action/reaction is at work? | The propeller pushes air backwards, and the air pushes back on the propeller and attached plane, moving it forward (thrust). |

How is a parked plane an example of Newton's 1st Law of Motion? | A parked plane will not move unless an unbalanced force acts on it. |

How is a plane in the air an example of Newton's 1st Law of Motion? | A plane in the air will fly at a constant speed if all the forces on it are balanced. |

What force resists the movement of the airplane through the air? | Drag |

Why do engineers try to decrease drag? | Drag slows down the plane and lessens fuel economy. |

What is the direction of drag? | Drag acts along and opposed to the direction of flight. |

What is thrust? | Thrust is a push forward along the direction of drag. |

Apply Newton's third law to thrust from a propeller. | As the propeller pushes the air backwards, the air pushes the propeller and attached plane forward. We call this forward force thrust. |

What word is applied to the up and down movement of a plane's nose? | Pitch |

What word is used to explain the movement of a plane's nose right and left? | Yaw |

When the plane rotates around the axis in the middle of the plane, we call that a _______ | Roll |

What is stability? | Stability is the property of an airplane to return to its original position when disturbed by an outside force. |

What three design features help create stability? | 1. dihedral wings (the wing tips are higher than where it attaches to the plane's body. 2. triangular tail shape which helps control pitch like arrow feathers. 3. A balanced center of gravity so it flies level. |

When all forces acting on an object cancel each other, so the net force is 0, we call them this: | Balanced forces |

Unbalanced forces result in a net force in some _______. | direction |

When unbalanced forces act on an object, the object does this. | Accelerates in the direction of the net force. |

If a plane is flying level at a constant speed, what can you tell about the 4 forces of flight acting on it? | The forces are balanced. |

When a plane is flying level at a constant speed, which of Newton's Laws of Motion is at work? | Newton's 1st Law of Motion: an object in motion remains in motion in the same direction at the same speed unless acted on by unbalanced forces. |

If a pilot applies more throttle, and the plane accelerates, which of Newton's Laws is at work? | Newton's 2nd Law of Motion: A net force exerted on an object will produce a proportional acceleration. |

The rate of change in speed of an object (speeding up or slowing down) | Acceleration |

Solve a practice problem (using 5 step method)What is the speed of a car that goes a distance of 125 km in 2 hours? | 62.5 km/h |

Solve a practice problem (using 5 step method) If a student takes 3 seconds to run to first base at an average speed of 6.5 m/s, what distance did she run? | 19.5 m |

Solve a practice problem (using 5 step method)A swimmer's average speed is 8 m/s. What will her time be in a 200 m race? | 25 s |

Solve a practice problem (using 5 step method) What is the acceleration of a skater that goes from 0 m/s to 6 m/s in 12s? | 05 m/s^2 |

Solve a practice problem (using 5 step method) If a water skier with a mass of 55 is pulled with a force of 110N, what will the acceleration be? | 2 m/s^2 |

Solve a practice problem (using 5 step method) What is the weight of a 65 km student on earth? | 637 N |