Resultant forces

Resultant force

a single force that has the same effect as all the other forces acting on an object

How to draw a free-body diagram?

Draw all forces from the centre of the object

How to find the F_R?

If single forces, subtract adjacent forces

If multiple, add forces in the same direction and subtract from forces on the other direction

Newton’s first law

If forces acting on an object are balanced, the resultant force is 0

• if the object is at rest, it remains stationary

• if it is moving, it will continue moving at the same speed in the same direction

Resultant force can…

1. Start motion

2. Stop motion

3. Speed up motion

4. Slow down motion

5. Change direction

6. Change shape

What is the effect of a resultant force called?

acceleration