# Why does the box stop? F=MA.

## Presentation on theme: "Why does the box stop? F=MA."— Presentation transcript:

Why does the box stop? F=MA

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

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

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

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

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

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

Equation 𝐹 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 =𝜇∗𝑀∗𝑔

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

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.

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

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