Forces and Interactions

• Speed and Direction are scalar quantities as they only tell you how fast something is moving or how far it has moved.

  An object can move at 10m/s but in any direction.
• Forces are vectors quantities
• velocity and displacement are vector quantities because they tell you how fast something is moving or how far you have travelled AND in which direction.
• Contact Forces

  • Friction
  • Air Resistance
  • water Resistance
  • Drag
  • Lift
  • Thrust/upthrust
  • Tension
  • Normal force= force exerted between forces which are touching but not moving.
• Non- Contact Forces

  • Gravitational ( Weight)
  • Magnetic
  • Electrostatic
• We use arrows to represent forces

  —————————>20N

  ——->5N

  • The lenght of the arrow represents the size of the force.
  • The arrow head shows the direction of the force.
• Newton’s 3 Law of Notion

  • For every action force , there is an equal and opposite reaction force.
• How do you apply Newton’s Law in a 4 marker

  1. Figure out the forces show in the diagram
  2. Label them
  3. Draw an arrow on the opposite direction of the action force. (Has to be same length as the action force arrow)
  4. Labelling opposite force