1. forces
Honors physics

2. What are forces?
A force is a push or pull upon an object resulting from the object's interaction with another object.
Whenever there is an interaction between two objects, there is a force upon each of the objects.
Forces only exist as a result of an interaction.

3. Two types of forces Contact Forces At-a-distance Forces
The two objects interacting must be touching.
Applied force
Friction
Normal force
Wind resistance
At-a-distance Forces
Objects do not need to touch for the force to exist.
Also known as field forces.
Gravitational force
Magnetic force
Electrical force

4. Contact force or Field force?

5. Identifying forces
There are many different forces that can act on an object and we have names for all of them! Fg = force of gravity (weight) FA = applied force (pushes or pulls from an object) FN = normal force (force pushing against gravity) FF = force of friction

6. Finding the net force
The net force is the sum of all the forces, taking into account the fact that a force is a vector and two forces of equal magnitude and opposite direction will cancel each other out.
FNET = +400 N
FNET = -200 N
FNET = -20 N

8. Free body diagrams (FBDs)
Let’s read the article and answer the questions.