•gravity- force of attraction between all objects.
• mass and distance between objects affect gravity.
•the shorter the distance, the greater the gravitational force.
• the greater the mass, the greater the gravitational force-the moons gravity is 1/6 of earths because it has less mass.
•velocity- the speed of something in a direction.
•acceleration-increase in the rate or speed of something.
•net force- the combination of acting an object.
• 0 (zero) net force- the forces are balanced-the speed remains at a constant so there is no change in the objects motion.
•net force is not zero- unbalanced forces-causes a change in speed, direction, or both (acceleration)
•the force must be large enough to overcome the objects inertia (resistance to change motion.
•acceleration occurs when an unbalanced net force acts on and object.