Physics Term 2

Force - A vector quantity that describes a push or pull on an object, having both magnitude & direction.

Effects of a force:

  • Set a body in motion 🏃🏼‍♀️

  • Modify the motion of an object ➡↩⤴

  • Deform the shape of an object 

Characteristics of a force:

  1. Point of application → the exact location where a force is applied to a body

  2. Line of action → horizontal, vertical, or oblique (diagonal)

  3. Direction → up, down, left, right, upright, upleft, downright, downleft. ⬆↖⬇↘➡

  4. Magnitude → numerical value of the amount of force applied on an object (Newton)


Types of forces

Contact forces

Non-contact forces (forces acting from a distance)

Can be exerted between 2 bodies physically in contact.

(Ex: Tension, Friction, Muscular, Buoyant, Drag forces)

Can be exerted WITHOUT physical touch between objects. 

(Ex: Magnetic 🧲, Gravitational, Electric force)



Common forces & their free body diagrams:

Weight: the gravitational force exerted by a planet on the object. Weight = Mass * Gravity 

For Weight, Electric & Magnetic forces, the P.O.A is the center of gravity of the body.


Hooke's Law for a Spring

  • Hooke's Law states that the force needed to stretch or compress a spring is directly proportional to the distance it is stretched or compressed.

Force = spring constant * change in length  (F = kx)


Force of Friction

  • Usually opposes the motion of a body as it slides over a rough surface 

It is a contact force, sometimes useful