1. Motion & Forces

2. Speed & Velocity
Speed - the rate of change in position over time (distance/time)
Instantaneous speed
Average speed
How is velocity different from speed?
Velocity describes both speed and direction

3. Change in Velocity
What makes an object change velocity?

4. Force Push or Pull Forces can cause a change in velocity Examples:
Gravity
Magnetism
Friction

5. Balanced Forces Forces that act on the same object
are opposite in direction
are equal in size

6. Balanced Forces Book on table Net force is zero
Weight of the book is downward force caused by gravity
Table pushes back with an equal and opposite force
Net force is zero

7. Unbalanced Forces CHANGE IN VELOCITY ACCELERATION
Forces that are NOT opposite and equal
What do they cause?
CHANGE IN VELOCITY
ACCELERATION

8. Friction Force that opposes motion between 2 surfaces Depends on the:
types of surfaces
force between the surfaces

9. Types of Friction Fluid friction: (Submarine)
Static Friction: (Couch Potato)
Force between objects at rest
Sliding Friction: (Ice skating)
Solid surfaces slide over each other
Rolling Friction: (Rollerblading)
An object rolls over a surface.
Fluid friction: (Submarine)
An object moves through a fluid

10. Friction Friction is greater... between rough surfaces
when there’s greater force between surfaces (such as more weight)

11. Lubricant
Changes sliding friction into fluid friction

12. Friction
Is friction always bad?

13. Gravity
The attractive force between all objects in the universe

14. Acceleration of Gravity
Near the surface of the earth the acceleration due to gravity is 9.8 m/s/s

15. Newton’s 1st Law
An object at rest remains at rest and an object in motion will continue moving at a constant velocity unless acted on by unbalanced forces.

16. Newton’s Laws of Motion

17. Newton’s 1st Law INERTIA
tendency of an object to resist any change in its motion
increases as mass increases

18. Newton‘s 2nd Law
If more force is applied, an object will be accelerated _____
more

19. Force = mass X acceleration
Newton’s 2nd Law
More force means more acceleration
More mass means less acceleration
Force = mass X acceleration
F = ma

20. Newton’s 3rd Law
For every action, there is an equal and opposite reaction.
Forces occur only in pairs
Act on different objects
Equal and opposite

21. Newton’s 3rd Law The hammer exerts a force on the nail to the right.
The nail exerts an equal but opposite force on the hammer to the left.

22. Momentum

23. Terminal Velocity
The final speed of a falling object.

24. Terminal Velocity
Air resistance is offsetting the the weight of the object

26. Forces
End

27. Force Aristotle's idea:
For an object to move at a constant speed, a constant force must be applied.

28. Force
Newton’s idea:
An object moving at a constant speed will continue at that speed without additional force being applied.

29. Balanced Forces