Physics-Resultant forces

What is a resultant force?

If you have a number of forces acting on a single point, you can replace them with a single force which has the same effect as the original forces acting all together. This single, overall force is the resultant force.

How to work out the resultant force?

If the forces on an object all act along the same line(in the same or opposite directions),, the resultant force is found by finding the sum of all the forces.

Free body diagrams

Each force is represented by an arrow, the length of the arrow shows the relative magnitudes of the forces and all the directions of the arrows show the directions of the forces.

Scale drawings

These can be used to find the resultant force acting on an object. First draw all the forces acting on an object ‘tip-to-tail’, making sure they’re to scale and all in the correct directions.

Then draw a straight line from the start of the first force to the end of the last force, this is the resultant force.

What is a balanced force?

If all forces acting on an object combine to give a resultant force of zero, the forces are balanced and the object is in equilibrium.

What is a resolving force?

Some forces act at awkward angles, to make things easier they are split into two ‘components’ at right angles to each other(usually horizontal or vertical). Acting together, these components have the same effect as the single force.