1. SSA Review - 9 Forces & Motion

2. 1 - What is FORCE?
Force- a push or a pull that one object exerts on another object
All forces have both direction and size
Measured in Newtons (N)

3. 2 - What are the two main categories of forces?
Contact Force (must be touching)
Non-contact forces (act at a distance)
*Air resistance
*Friction
*Gravity
*Electrical force
*Magnetic force

4. A) Contact Forces
Contact force- type of force that result when two objects are physically contacting each other
Air resistance
Friction

5. A) Contact Forces
Air resistance

6. A) Contact Forces
Friction

7. Balanced vs. Unbalanced
Balanced forces- forces that are equal in size but opposite in direction
Results in no movement

8. Balanced vs. Unbalanced
Unbalanced forces- forces that are unequal in size and may or may not be opposite in direction
Results in acceleration

9. Why is the motion towards the right in the bottom picture above?

10. Net Force
Net force is the total of all forces acting on an object.
If the net force is zero, the forces are balanced.
If the net force is not zero, the forces are unbalanced.

11. Net Force Examples
Which direction will the ball move and with how much force?

12. Practice!

13. B) Non-Contact Forces Push or pull without touching
Electrical force- force between two charged objects
Static cling
Magnetic force- attraction or repulsion of two magnetic poles
Magnets
Gravitational force- the force that pulls objects straight down toward the center of the earth
A dropped object falling to the ground

14. Factors Affecting Gravity
Law of Universal Gravitation
Mass
-- The more mass an object has, the
greater the gravitational force
between it and other objects.
Distance
As distance increases, gravitational force decreases.

15. Mass vs. Weight Weight - the amount of gravitational pull on an object
Mass - the amount of matter in an object

16. 2 - Speed & Direction Speed – the rate of motion
Speed = Distance ÷ Time

17. 3 - Speed & Direction Acceleration – a change in speed or direction
Positive acceleration – speeding up
Negative acceleration – slowing down
When an object moves either at a constant speed or is stationary, the forces are balanced.

18. Distance vs. Time Graph
Ashley is drawing a graph that shows four different objects and the distance each object travels in 5 seconds. Which line on the graph shows the object that is traveling with the fastest constant speed?
A. Line A B. Line B C. Line C D. Line D

19. Distance vs. Time Graph
Which line on the graph shows the object that is traveling with a changing speed?
A. Line A B. Line B C. Line C D. Line D

20. 3 - Newton’s Laws of Motion

22. An object’s acceleration depends on the mass of the object and the force applied to it

23. For every action, there is an equal and opposite reaction.
For every action, there is an equal and opposite reaction.