An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

The tendency of an object to resist changes in its state of motion.

A coordinate system from which motion is observed that is not accelerating (moving at a constant velocity).

When all forces acting on an object are balanced (net force = 0), the object is in equilibrium. It will either remain at rest or continue moving at a constant velocity.

A measure of an object's resistance to changes in its motion. The more massive an object is, the harder it is to accelerate.

This is determined by how strongly an object is attracted to other objects due to gravity.

Gravitational Mass: Determined by gravitational attraction. | Inertial Mass: Determined by resistance to changes in motion.

Mass: A measure of inertia (how hard it is to accelerate something). | Weight: The force of gravity on an object ($W=mg$).

1. Measure mass. 2. Apply varying forces. 3. Measure acceleration. 4. Record data. 5. Plot force vs. acceleration. 6. Examine the relationship.

1. Place the golf ball on one side of the balance. 2. Place known masses on the other side until balanced. 3. The known masses will equal the gravitational mass of the golf ball.

1. Apply a known force to the golf ball. 2. Measure its acceleration. 3. Use Newton's Second Law ($F=ma$) to calculate inertial mass ($m=F/a$).