1. What is force?
FORCE = A push or pull that changes an object’s velocity
A change in velocity = acceleration
As a result, forces can cause objects to speed up, slow down, or change direction

2. What are the units for force?
UNIT: Newton (N)
Measurement
Unit
Distance
Meters (m)
Time
Seconds (s)
Velocity
m/s
Acceleration
m/s2
Force
Newton (N)

3. What is Net Force? Usually more than one force is acting on an object
NET FORCE = combination of all the forces acting on an object

4. What are Balanced Forces?
Forces are balanced when the net force = 0
Equal forces going in opposite directions
NO ACCELERATION
Object is said to be in equilibrium

5. What are Unbalanced Forces?
Forces are unbalanced when net force ≠ 0
One force is greater than another
Acceleration occurs

6. Quick Checks What is net force?
What is true about net force when all the forces acting on an object are balanced?
What does this mean for the motion of the object?
What is true about net force when all the forces acting on an object are unbalanced?

7. Equilibrium Video

8. Video Qs What is tension? (force in stretched rope)
What is the equilibrium rule?
(∑F=0 if the system doesn’t change its state of motion)
∑ - sigma – sum of
What would happen to the tension in Burl’s rope if Burl and Hewitt were both on Burl’s side?
(Burl’s rope would have ALL the tension – the force would increase)