GEN PHYS 1 | Momentum, Impulse, and Collisions

Centroid

known as the geometric center, the average position of all the points in a symmetrical object; tt depends only on the shape and size, not on mass

Center of Mass

the average position of the mass in a system, it considers how mass is distributed within the object or system

Momentum

• restatement of Newton’s Second Law of Motion

• “quantity of otion”

• product of mass and velocity

• measured in units of kilograms-meters per second

Impulse

• force applied over a period of time

• measured in unit newton-second (Ns)

• denoted as J

• measure of the interaction over time between an object and an external force

Conditions for Conservation of Momentum

• the system should be isolated

• no external impulse or forces

• balanced external forces (if present)

• short interaction time

Isolated System

• A system where only internal forces (e.g., action-reaction pairs) are acting.

• No net force from outside the system acts on it, or external forces cancel out.

Collisions

occur when two or more bodies interact or make contact with each other

Coefficient of Restitution

determines how bouncy an object is in a collision

Elastic Collisions

• total momentum and total kinetic energy are conserved

• the objects bounce off without lasting deformation or heat generation

• coefficient of restitution is 1

Inelastic Collisions

• momentum is conserved, but some kinetic energy is transformed into other forms like heat, sound, or deformation energy.

• objects still separate after the collision.

• coefficient of restitution is between 1 and 0

Perfectly Inelastic Collisions

• momentum is conserved, but some kinetic energy is transformed into other forms like heat, sound, or deformation energy.

• objects still separate after the collision.

• coefficient of restitution is 0