Gravity
Gravity is a force that always attracts or pulls object towards each other without direct contact or impact.
Factors that influence Gravitational Attraction: Mass and Distance
Gravity keeps us on Earth and keeps all objects in orbit (EX. The Moon continues orbiting around Earth because Earth's gravity pulls it in.)
Gravity can also cause objects to change speed, direction, or both. An object dropped will continually increase speed as it falls because gravity is constantly pulling down on it. This can also happen to an object thrown into the air. The object can change speed and direction as it changes its upward motion, slows down, and falls back to Earth.
If air resistance is ignored, all objects will fall at the same rate. This can be created in a vacuum (empty space). This is possible because there is nothing to slow either object down. so the only force acting on the objects is the pull of gravity.
Factors that influence Gravitational Attraction: Mass and Distance
Gravity keeps us on Earth and keeps all objects in orbit (EX. The Moon continues orbiting around Earth because Earth's gravity pulls it in.)
Gravity can also cause objects to change speed, direction, or both. An object dropped will continually increase speed as it falls because gravity is constantly pulling down on it. This can also happen to an object thrown into the air. The object can change speed and direction as it changes its upward motion, slows down, and falls back to Earth.
If air resistance is ignored, all objects will fall at the same rate. This can be created in a vacuum (empty space). This is possible because there is nothing to slow either object down. so the only force acting on the objects is the pull of gravity.
Friction
Friction is a force that occurs when two surfaces rub together. Heat is produced from friction. (Think about rubbing your hands together really quickly)
The factors that determine the amount of friction are the kinds of surfaces and that force pressing them together.
Friction can slow down or stop the motion of an object. This force always acts in the opposite direction of the motion. It can also be the force that makes it difficult to start moving an object. To move an object, the force applied must be greater than the force of friction.
EX. Tennis shoes with grooved tread increase friction as opposed to smooth soled dress shoes.
The factors that determine the amount of friction are the kinds of surfaces and that force pressing them together.
Friction can slow down or stop the motion of an object. This force always acts in the opposite direction of the motion. It can also be the force that makes it difficult to start moving an object. To move an object, the force applied must be greater than the force of friction.
EX. Tennis shoes with grooved tread increase friction as opposed to smooth soled dress shoes.