1. Calculating Force and Types of Friction
Forces
Calculating Force and Types of Friction

2. Force: A push or pull exerted on an object
A force is described by its strength and by the direction in which it acts
SI Unit of Force = newton (N)
Sir Isaac Newton

3. Net Force: Sum of all forces acting on an object
The change in motion of an object is determined by the net force
You can find the net force by adding together the strengths of all the individual forces
Any nonzero net force causes a change in motion

4. Calculating Net Force:
Example: 2 forces pushing on an object from the right Net Force = 8N moving the box to the Right 5N 3N 8N

5. What is the net force for each situation?
State whether the forces are Balanced or Unbalanced

6. What about this situation?
Balanced Forces:
result in no movement of the object
Unbalanced Forces:
the object will move in the direction with the larger applied force

7. Friction acts in the direction opposite of the object’s motion
Friction: The force that two surfaces exert on each other when they rub together
Two factors that affect the force of friction
1. The surfaces involved
2. How hard the surfaces are pushed together
Smooth surfaces produce less friction
Friction acts in the direction opposite of the object’s motion

8. Types of Friction Sliding: when 2 solid surfaces slide over each other
* Makes moving objects slow down or stop
Static: acts on objects that are NOT moving
* Force that keeps you from moving
Fluid: when a solid object moves through Water or Air
Rolling: occurs when an object Rolls across a surface

9. Gravity: the force that acts to pull objects straight down toward the center of the earth
Universal Gravitation: states that ALL objects are attracted to each other
2 factors that affect Gravitational Attraction
* Mass and the Distance between the objects
The greater the mass, the great the gravitational force
As distance increases, gravitational force decreases

10. Calculating Force: Force = mass X acceleration
F = ma
Force = mass X acceleration
This formula calculates the amount of force that
must be applied to an object to accelerate it