1. Why does the box stop?
F=MA

2. Friction is the force resisting the motion of objects sliding against each other.
Box
Surface
Friction is a force!

3. Friction always apposes motion
F=MA
Friction
Force
Friction
Force
Friction always apposes motion

4. Three types of friction
Static Friction
Static means “no motion”
Static friction is the friction force that prevents two surfaces at rest from sliding past each other.
As you apply force, friction force increases
Apply Force
Friction Force
When applied force is greater than friction force,
the object begins to move

5. Three types of friction
Sliding Friction
Sliding friction is the friction force that opposes the motion of an object along a surface.
Static friction is before an object moves
Sliding friction is when the object is in motion

6. Three types of friction
Rolling Friction
Rolling friction is the friction force that opposes the motion of a circluar object along a surface.

7. Three types of friction
>
>
Static Friction
Sliding Friction
Rolling Friction
All friction opposes motion

8. Equation
𝐹 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 =𝜇∗𝑀∗𝑔

10. Newton’s First Law More Mass = More Inertia
Also called: Newton’s Law of Inertia
Inertia is the resistance to motion due to mass
More Mass = More Inertia

11. Elephant has more inertia ‘
Example
Elephant has more inertia ‘
than a human
Which means, it’s harder to change an elephant’s motion than a human’s motion.

12. More inertia, means more force to get it moving
50 kg
Force
More Mass = More Inertia
100 kg
2 x Force
More Inertia = More Resistance
150 kg
3 x Force

13. Friction Force
Depends on surface and shape of object
Inertia
Depends on mass of the object