Idealizations in Mechanics

Real-world systems are often complex. To make problems manageable, physicists use simplified models.

Particle Model

In many cases, we treat an object as a particle, meaning:

• Its size is negligible
• Only its mass and position are considered

This approximation is valid when the object's dimensions do not significantly affect the motion.

Examples:

• Earth orbiting the Sun
• A car moving along a highway

Rigid Body

A rigid body is an object in which:

• The distance between any two points remains constant
• No deformation occurs under applied forces

This model is useful when studying rotational motion.