Friction

Question 1

Cons of friction

Answer 1

→ Slows things down (drag force, like air or water resistance)
→ Damages/Wears up moving parts
→ Heats up moving parts (engine)

Question 2

Pros of friction

Answer 2

→ Necessary for you to move eg. you walk or run
→ Can be used to start chemical reactions (eg. fire)
→ Allows braking for cars, bikes, and stops skidding

Question 3

How to measure friction?

Answer 3

We measure friction by measuring the force we use to overcome friction, when the resultant force is 0 (the object is moving at constant speed).
The more friction there is, the more force we need to overcome it.

Question 4

Does mass or weight affect friction?

Answer 4

Yes. Mass, or weight, affects friction, but not surface area.

Question 5

Where is there no friction?

Answer 5

Space. There is no friction in space as it is a vacuum, so there is nothing to resist it.

Question 6

Is there friction in water and air?

Answer 6

No, but there is air and water resistance, and they’re very similar.

Question 7

How to reduce friction?

Answer 7

—> lubricate the surfaces (grease, oil, water)
—> use ball bearings
—> make the surfaces smooth
—> reduce the force pushing the surfaces together

Question 8

What is friction?

Answer 8

Friction is the contact force that slows down moving things.