Physics: Vectors and Scalars

Vectors and Scalars

• A vector has both magnitude and direction.
• A scalar has only magnitude.
• Scalars are generally non-negative, but vectors can be negative as they have a direction associated with them.

Examples of Vectors and Scalars

• Speed is a scalar quantity.
• Velocity is a vector quantity.
• Distance is a scalar quantity.
• Displacement is a vector quantity.
• Time is a scalar quantity.
• Momentum is a vector quantity.
• Acceleration is a vector quantity.
• Energy is a scalar quantity.
• Force is a vector quantity.
• Mass is a scalar quantity.

Displacement and Velocity

• Displacement can be negative if the direction is considered (e.g., a ball thrown off a cliff).
• The zero point of a vector can be chosen arbitrarily, depending on the context (e.g., setting the zero point at the bottom of a cliff).
• Velocity is speed with direction (e.g., 10 m/s vs. 10 m/s at 30° above the horizontal).
• Even if the speed is constant, the velocity can change if the direction changes (e.g., a car traveling around a roundabout).

Representing Vectors

• Vectors can be represented by arrows, with their size/length representing the vector magnitude.

Object Interaction

Forces

• A force is a push or pull that acts on an object due to interaction with another object.
• Forces can be classified into two types:
  • Non-Contact Forces:
    • Electrostatic forces (caused by charges)
    • Gravitational forces (caused by mass)
  • Contact Forces:
    • Normal contact force (opposite direction to contact)
    • Friction (caused by surface roughness when moving in contact)

Distinguish between vectors and scalars in physics, understanding their differences in magnitude and direction. Examples include speed, velocity, distance, displacement, and more.