Gravity is not just a good idea ! It’s the LAW!!!

Laws of Motion Notes

Law of Gravity All objects that have mass have gravity. The pull of gravity between any 2 objects depends upon the mass of the 2 objects and the distance between them. Weight is a measurement of gravitational pull. Mass does not depend upon gravity, mass depends upon amount of matter in something, but on the Earth, they are basically the same. (Causing confusion!)

Astronauts training on the “Vomit Comet” The are in “free fall” so they appear to have no weight since they have no support.

First Law of Motion This law is sometimes called the law of Inertia (EENERSHA) Inertia is the property of a moving object to keep moving unless something stops it. http://www.youtube.com/watch?v=fPI-rSwAQNg

More First Law of Motion Friction is a force that causes objects to change their motion When friction occurs, it produces heat. (Ever had a rope burn?)

More First Law of Motion Another part of the First Law of Motion is that an object at rest will stay at rest unless some force causes it to move. http://www.youtube.com/watch?v=CyhVSus7LFM

2nd Law of Motion This law basically says that the more force applied to an object, the more it will be accelerated, and thus the more it will move. Ex. The harder you throw a baseball, the more distance it will travel.(other variables not considered here)

3rd Law of Motion This law states that for every action, there is an equal and opposite reaction. Example: On ice skates, you push against the boards, you move backwards.

Terminal Velocity (Speed) Definition: the maximum speed attained by a falling object Air resistance (Friction) determines terminal velocity An open parachute has a lower terminal speed than a free falling sky diver because it has more friction. A Rock would have a higher terminal speed than a feather does? Why?

Question ? Would a object falling to the surface of the moon have a terminal velocity? Answer: No, an object falling on the moon would not have a terminal velocity because there is NO AIR RESISTANCE on the Moon

Acceleration Due To Gravity A falling object will increase it’s speed as it falls. The speed stops increasing (no more acceleration) once the air resistance equals the gravitational pull Acceleration due to gravity is 9.8 m/s/s. (Ignoring air resistance) http://www.youtube.com/watch?v=5C5_dOEyAfk http://www.youtube.com/watch?v=xrjosOjvlOc