Physics Fundamentals: Forces, Motion, and Vectors

Forces and Motion

An outside influence that changes a body's state of rest or motion is called force.

Types of Forces

Normal Force: The force perpendicular to a surface exerted on a body by that surface.

Friction: A force resulting from physical contact between a body and its surroundings, opposing motion.

Gravity: A force proportional to acceleration, attracting objects with mass towards each other.

Fundamental Forces: Gravity, Electromagnetic, Strong Nuclear, and Weak Nuclear.

Newton's Third Law

Also known as the Law of Action and Reaction.

Inertial Reference Frame

A frame where a body moves with constant speed if no force acts on it.

Work and Momentum

Work

A scalar quantity obtained from the product of force and displacement.

Momentum

Define this formula:

The momentum of a particle is a vector quantity equal to the product of its mass and velocity.

Collisions

Types of Collisions

• Elastic Collisions: Collisions where energy and momentum are conserved.
• Inelastic Collisions: Collisions where kinetic energy is not conserved.
• Completely Inelastic Collisions: Collisions where objects stick together after impact.

Units and Measurements

International System (SI)

Also known as MKS units, defined in terms of length, mass, and time.

Derived Units

Examples: Area, Volume, Speed, Acceleration, Force, Power.

Scalar Quantity

A quantity represented by a number and its units, e.g., Scalar.

Vectors

Vector Characteristics

A vector has direction, magnitude (scale with units), and sense (positive or negative).

Parallel Vectors

Vectors with the same direction.

Vector Addition

Vector addition properties:

Unit Vectors

Vectors with magnitude 1 and the same direction as the original vector.

Scalar Multiplication

Multiplication of vectors resulting in a scalar.

Kinematics

Speed

Change of position with respect to time.

Acceleration

Speed variation with respect to time.

Free Fall

An object falling under gravity with constant acceleration (ignoring air resistance).

Parabolic Motion

Movement towards a constant speed in free fall motion.

Uniform Circular Motion

Motion in a circle with constant speed but changing direction.

Centripetal Acceleration

Acceleration pointing towards the center of the circle.