1. Unbalanced forces
Unbalanced forces lead to a change in speed or direction.
What if only one wind machine is blowing on the skater?
The forces acting on her are no longer balanced so she
will start to move to the left. Her speed will change – this
is called acceleration.

2. 11 N 10 N
What happens if the pull on one end is greater than the pull
on the other end?
unbalanced forces
movement
When forces are unbalanced
The forces acting on the hooks are no longer balanced.
Both hooks will start to move to the left – their speed will
change. This is called acceleration.
Unbalanced forces lead to a change in speed or direction.