1. Forces
May they be with you 

2. What is a force?
A force is defined as the push or pull on an object.

3. Forces Some common types of force Fg = force of gravity
Ff = force of friction
Ft = force of tension
Fn = normal force
Fa = applied force
Fnet = sum of all forces

4. What are the different types of forces?
1. GRAVITY – is a force that pulls down on objects Fg

5. What are the different types of forces?FN Fg
2. NORMAL– is the force a surface “pushes” into an object Fg FN
If the surface is flat, normal force pushes straight up. (90°)
If the surface is angled, the normal force “looks” angled. (but is 90° to the surface)

6. What are the different types of forces?
3. FRICTION– is a force that appears whenever two things are in contact.
No matter which direction
something moves in,
friction pulls it the other way.

7. What are the different types of forces?
4. TENSION– is a pulling force exerted by a string, cable, chain, or rod on another object. FT
Tension is the opposite of compression. FT FT

8. What are the different types of forces?
5. COMPRESSION– a pushing force exerted on another object. for ex; spring FC

9. HOW FORCES “BEHAVE” Forces follow three basic laws called
Newton's laws

10. Newton’s Laws of Motion

11. 1st Law of Motion An object at rest will stay at rest unless acted on.
An object in motion will stay in motion unless acted on.

12. 1st Law of Motion “objects will stay doing what they are doing”
The tendency of an object to resist a change in their motion is called Inertia
The more mass an object has the more inertia it has

13. 2nd Law of Motion
Force is equal to mass times acceleration

14. 2nd Law of Motion
F=ma
The acceleration of an object depends on the net force acting on an object.
Net force = the addition of all the forces acting on an object

15. 3rd Law of Motion
For every action there is an opposite and equal reaction

16. Mass vs. Weight Mass – how much matter is in something
Weight – how much something is pulled by gravity. Depends on where you are located

17. Force of Friction Occurs when two objects are in
contact with each other.
Coefficient of friction (μ – mu)
μ= friction force/weight
The coefficient of friction depends on whether the object is sliding or not.
If the object is sliding μ is slightly less
This is called sliding or kinetic friction
When friction holds an object at rest we call it static friction.