Force

Definition

Force is any interaction that, when unopposed, will change the motion of an object. It can cause an object with mass to change its velocity (to accelerate).

5 Must Know Facts For Your Next Test

1. Force is a vector quantity, having both magnitude and direction.
2. The unit of force in the International System of Units (SI) is the Newton (N).
3. Newton's Second Law states that Force equals mass times acceleration ($$F = ma$$).
4. Forces can be categorized as contact forces (e.g., friction, tension) or non-contact forces (e.g., gravitational, electromagnetic).
5. The net force acting on an object is the vector sum of all individual forces acting on it.

Review Questions

• What is the unit of force in the International System of Units?
• According to Newton's Second Law, how do you calculate force?
• What distinguishes contact forces from non-contact forces?

Related terms

Newton's First Law: An object at rest stays at rest and an object in motion stays in motion unless acted upon by a net external force.

Mass: A measure of the amount of matter in an object, typically measured in kilograms.

Acceleration: The rate at which an object's velocity changes with time.