Resultant forces and work done

• Free body diagrams

  • the sizes of the arrows show the relative magnitudes of the forces
  • the directions of the arrows show the direction of the forces acting on the object
• A resultant force is the overall force on a point or object

  • If you have a number of force acting at a single point, you can replace them with a single force
  • this single force is the resultant force
  • If the forces all act along the same like (they are parallel ) , the overall effect is found by adding those going in the same direction and subtracting any going in the opposite direction
• If a resultant force is the overall tone on a point or object
• work done (J) = Force (N) x Distance (m)
• scale drawing

  • Draw all the forces acting on an object to scale
  • then draw a straight Line from the start of the first force to the end of the last force, this is the resultant force
  • Measure the length of the resultant force on the diagram to find the magnitude and the angle to find the direction of the force
• An object is in Equilibrium it the forces on it are balanced

  • If all the forces acting on an Object combine to give a resultant force of zero, the object is in equilibrium
  • on a scale diagram this means that the tip of the last force you drew should end where the tail of the first force you drew begins
• you can split a force into components

  • Not all forces act horizontally or vertically, some act at awkward angles
  • To make these easier to deal with, they can be Split into two components at right angles to eachother
  • Acting together, these components have the same affect as a single tone
  • you resolve a force (split it into components ) by drawing it on a scale grid. Draw the force to scale, then held the horizontal and vertical lines in a triangle