Wheels Flashcards

You may prefer our related Brainscape-certified flashcards:
0
Q

Wagon-less Wagon experiencing 3 forces?

A

1) It’s downward weight
2) Support force from surface
3) Horizontal frictional forces from surface (violates N’s1st law?)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Friction?

A

Forces exerted by surfaces on each other.

  • Adheres N’s 3rd Law (all forces)
  • Acts parallel (along) surfaces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Frictional Forces oppose____?

A

relative motion b/w two surfaces in contact

  • exerted parallel to the surfaces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Relative Motion

A

Motion against velocity’s directio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Surfaces in contact produce friction that has the same____?

A

Velocity, objects move together vs sliding across each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Frictional Forces are____ external forces on objects

A

Opposite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Hold can w/ 2 fingers, exerting any frictional forces on can? In what direction forces?

A

Yes, exerting upward frictional force on can (your relative motion opposed by cans’ downward weight)
& .•. support cans’ weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Surfaces at rest & in contact ____ into____ _____ & are .•. particularly _____ to the ____ of ______.

A
  1. Each other

2. Resistant to the start of sliding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Friction depends (3)

A
  • type of surface
  • pressure of surfaces against each other
  • whether/not surfaces actively sliding across
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Frictional Forces dependant on?

A

Support forces,

a bigger support force b/w 2 surfaces = bigger frictional forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

of contact points proportional____

A

of support forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Contact points responsible for?

A

Frictional forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Amontons 1st law of friction?

A

Frictional forces b/w 2 surfaces are proportional to support forces b/w them.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Amontons 2nd Law Friction

A

Frictional Forces b/w 2 surfaces don’t depend their apparent contact area.
- Surface you see touching floor not really (all) surface touching floor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

For any two surfaces,

coefficient of friction = ?

A

frictional force (forces available when try sliding them/ support force (b/w 2 surfaces)

  • typically 0.5, 0.3 etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Frictional forces b/w tire & surface allow you to (3)?

A

1) speed up
2) slow down
3) turn

  • w/out frictional you’d be inertialo
16
Q

Want tires that (2)

A

1) grip road well (higher coefficient of friction)

2) wheels tightly pressed against road producing higher support force b/w road & tire.

17
Q

Static Friction

A

Surfaces touching & not sliding across each other.

- forces causing surfaces not move (experience 0 net force & 0 acceleration

18
Q

Sliding Friction

A

Objects coasting across each other.

19
Q

The harder press 2 surfaces together___ the higher/lower (?) ___ ____ _____ can obtain

A

Higher peak static friction it can obtain

20
Q

Static friction is ____ & there’s a ____ of static friction before moving.

A

Adjustable & there’s a limit of static friction before moving.

21
Q

When gives up/at its limit frictional force turns into?

A

Sliding Friction

22
Q

When sliding box across floor need higher/lower force to start moving vs force keep box coasting?

A

Need higher force when first move box vs lower force needed keep coasting

23
Q

Coulomb’s 3rd Law of Friction

A

Sliding frictional forces are independent of sliding speed.

  • faster you push/pull doesn’t affect force applied
24
Q

Sliding friction always in direction that____ ____ _____ to _____

A

Direction that opposes relative motion to surfaces.

25
Q

Static friction or Sliding friction higher force & better grip?

A

Static friction.
- mountain peaks grip together & settle in to make higher friction
vs
- mountain peaks sliding across each other.

26
Q

Is sliding friction adjustable & what does it depend on?

A

It’s not adjustable & it depends on how hard surfaces press each other (obey coulombs 3rd law friction)

27
Q

Sliding Friction wastes

A

Energy.

28
Q

(For moving box) sliding friction converts box’s ____ energy into ____ energy.

A

Kinetic energy into thermal energy.

29
Q

When box slides to stop on motionless floor, who does work on other?

A

Floor does negative work on box (pushes box opposite direction its velocity) &
Box does 0 work on motionless floor even though pushing on it.