Force

Force

1. Mass (m)

   • Amount of matter in a body
   • Scalar quantity
   • Kilogram (kg)

2. Momentum (p)

   • Mass x velocity
   • kg m/s
   • Principle of conservation of momentum
     • Total momentum before an interaction is equal to the total momentum after
       • Provided no resultant force acts on the system
   • Vector quantity

3. Force

   • That which can cause acceleration
   • Vector quantity
   • Newton (N)
     • 1 N = 1 kg m/s²
   • Moment
     • Force x perpendicular distance to the fulcrum
   • Lever
     • Rigid body that is free to rotate about a fixed axis
   • Couple
     • A pair of equal and opposite forces whose lines of action do not coincide
   • Torque
     • The magnitude of one of the forces in a couple multiplied by the distance between them

4. Newton's Laws of Motion

   • Linear Motion: Newton's Equations of Motion
   • A body will remain at rest or continue moving at constant velocity unless acted on by an external force
   • The rate of change of momentum is proportional to the applied force and takes place in the direction of the force
     • F = ma
   • For every action there is an equal and opposite reaction

5. Gravity

   • Newton's Law of Universal Gravitation
     • Any two objects exert a gravitational force upon each other
   • Centre of gravity
     • The point at which the whole weight of a body appears to act

6. Friction

   • A force that opposes the motion of a body

7. Weight

   • A force
   • Mass x gravity
   • Newtons