Centripetal force (help....) (1 Viewer)

[deswa1]

Hi guys,

Just two questions:
1. When a car is going around a curve, in order to avoid flying off does the friction force have to equal the centripetal force or can it be greater?
2. What forces cause a change in velocity in a car going around an icy curve?

Thanks heaps

 

[Fizzy_Cyst]

Hi guys,

Just two questions:
1. When a car is going around a curve, in order to avoid flying off does the friction force have to equal the centripetal force or can it be greater?
2. What forces cause a change in velocity in a car going around an icy curve?

Thanks heaps

1. The frictional force must be high enough to provide the needed centripetal force for the car to round the curve. I.e. Frictional force must be greater than or equal to centripetal force.
2. The same forces as on a regular curve, its just that the frictional force would be much smaller, thus would have to travel around the curve at a much lower velocity

 

[deswa1]

Thanks a lot.

So basically for the second question, the forces are inertia (for), air resistance (against) and centripetal force (sideways)?

 

[Drongoski]

Thanks a lot.

So basically for the second question, the forces are inertia (for), air resistance (against) and centripetal force (sideways)?

What?

 

[deswa1]

AS in, the forces affecting the cars motion are:
Inertia in the direction of motion
Air resistance against the direction of motion
Centripetal forces sideways

Or am I looking at this the wrong way?

 

[Drongoski]

From the little bit of physics I know, I'm confused.

 

[clementc]

Of those, only air resistance is a real identifiable force. Inertia is not a force but rather a tendency of the body to resist acceleration (it can be considered to be essentially equivalent to mass).
Centripetal force is the sum of the forces that add up to allow the car to travel in a circle - it's not like a direct force like friction, tension, electrostatic attraction, etc.

So the forces I can think of which would affect a car's velocity on an icy (assuming frictionless) road are
- Friction between the internal parts of the car, slowing down the car
- Air resistance if you're really desperate, which also slows down the car

With nothing to provide a centripetal force on a smooth road, the car won't turn in a circle, and so the direction of the velocity will not change.

But to be honest I reckon this is a pretty dodgy question =\

 

[romesh]

So the forces I can think of which would affect a car's velocity on an icy (assuming frictionless) road are
- Friction between the internal parts of the car, slowing down the car
- Air resistance if you're really desperate, which also slows down the car

If it is a frictionless road, then friction between the internal parts of the car won't matter. You can see this by imagining the car sliding on the frictionless road without the wheels turning or any other parts within the car moving- it will keep sliding until an external force acts on it. For a truly frictionless road, air resistance is the only force that can affect the car