.....................is a force that pulls objects together. On Earth, it is a force that pulls all objects to Earth's center.

..................is the amount of matter in an object

...................is a force caused by two things rubbing against each other.

................and.................are forces that affect the motion of all objects.

Forces that are equal in size and opposite in direction are called...............

Forces that are not equal in size and opposite in direction are called ....................

..................of motion explains how acceleration, force, and mass are related. It says an object's acceleration depends on the mass of the object and the size of the force acting on it.

The same ..................will accelerate a small mass more than a large mass.

The downward force is and the upward force is .