Fundamental Laws of Motion to Know for AP Physics C: Mechanics (AP)

Newton's First Law of Motion (Law of Inertia)

An object remains at rest or in uniform motion unless acted upon by a net external force.

Inertia

The tendency of an object to resist changes in its state of motion, directly proportional to its mass.

Newton's Second Law of Motion

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Newton's Second Law Formula

Fnet​=ma, where FnetF is net force, m is mass, and a is acceleration.

Newton's Third Law of Motion

For every action, there is an equal and opposite reaction.

Conservation of Linear Momentum

The total momentum of a closed system remains constant unless acted upon by an external force.

Momentum Formula

Momentum (p) is calculated as p=mv, where m is mass and v is velocity.

Work-Energy Theorem

The work done on an object is equal to the change in its kinetic energy.

Conservation of Energy

Energy cannot be created or destroyed; it can only transform from one form to another.

Conservation of Angular Momentum

The total angular momentum of a system remains constant if no external torque acts on it.

Kepler's First Law

Planets orbit the Sun in elliptical paths, with the Sun at one focus.

Kepler's Second Law

A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.

Kepler's Third Law

The square of a planet's orbital period is proportional to the cube of its average distance from the Sun.

Acceleration

The rate of change of velocity of an object with respect to time.

Net Force

The vector sum of all the forces acting on an object.

Friction

The force that opposes the relative motion of two surfaces in contact.

Kinetic Energy

The energy possessed by an object due to its motion, calculated as KE = 1/2 mv².

Potential Energy

The energy stored in an object due to its position or configuration, often due to gravity, calculated as PE = mgh.

Torque

A measure of the force that causes an object to rotate about an axis.

Equilibrium

A state in which all the forces acting on an object are balanced, resulting in no net force and no acceleration.

Pressure

The force applied per unit area, commonly measured in Pascals (Pa).

Energy Transformation

The process of changing energy from one form to another, such as potential to kinetic energy.

Law of Universal Gravitation

Every point mass attracts every other point mass with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.

Angular Velocity

The rate of change of angular displacement with respect to time, usually measured in radians per second.

Centripetal Force

The inward force required to keep an object moving in a circular path, directed towards the center of rotation.

Mechanical Energy

The sum of potential energy and kinetic energy in a system.

Free Fall

The motion of an object where gravity is the only force acting upon it.

Force

An interaction that, when unopposed, will change the motion of an object.

Mass

The amount of matter in an object, typically measured in kilograms.

Velocity

The speed of an object in a specific direction.

Gravitational Potential Energy

The potential energy an object has due to its height above the ground, calculated as PE = mgh.

Elastic Potential Energy

The potential energy stored in an object when it is compressed or stretched, such as in a spring.

Circular Motion

The motion of an object traveling along a circular path.

Work

The process of energy transfer that occurs when a force is applied over a distance.

Instantaneous Speed

The speed of an object at a specific moment in time.

Average Speed

The total distance traveled divided by the total time taken.

Newton's Law of Gravitation

The principle that relates the gravitational force between two masses.

Speed

The distance traveled per unit of time, without regard to direction.

Impulse

The change in momentum resulting from a force applied over a period of time.