Free body Diagram and Resultant force

• • Resultant force is the sum of the forces acting on an object
• How to calculate Resultant force

  • First rule: If the forces acting on an object are all in the same direction , then we calculate the resultant force by adding the forces together. The direction of the resultant force is the same as the direction of the other forces.
• How to calculate Resultant force

  • Second Rule: If the forces acting on an object are in opposite directions , then we calculate the resultant force by subtracting the smaller force from the bigger force. The direction of the Resultant force is the same direction of the bigger force
• How to calculate Resultant force

  • Third Rule: If the forces are at a right angle , then we calculate the resultant force by using Pythagoras’s theorem.

  
• How to draw a Free body diagram

  1. All the forces act from the centre of the object (centre of mass).
  2. The length of the arrow represents the size of the force.
  3. The direction of the arrow shows the direction of the force.
• A free body diagram is a diagram which shows all the forces exerted on a singe object