# A car goes around a curve. Why is the friction towards the center of the curve and not outwards?

#### lemniscate314

I thought that friction opposed the direction of the motion? What I usually do to figure out where the friction points is that I try to imagine what would happen if there was no friction. Since there is an inclination, if the road were made of ice the car would slide inwards, towards the curve. I also thought that by definition friction had to oppose motion necessarily. I don't understand.

EDIT: In other words, what is pushing the car outwards?

Last edited:

#### Cervesa

In other words, what is pushing the car outwards?
Nothing is "pushing" the car outward. The car's inertia causes the car to continue in a straight line according to Newton's 1st Law of motion. Friction and the horizontal component of the Normal force of the incline overcomes this tendency to stay on a straight path by pushing in toward the center (centripetal force) which allows the car to remain in a curve.

studiot

#### studiot

Nothing is "pushing" the car outward. The car's inertia causes the car to continue in a straight line according to Newton's 1st Law of motion. Friction and the horizontal component of the Normal force of the incline overcomes this tendency to stay on a straight path by pushing in toward the center (centripetal force) which allows the car to remain in a curve.

Can you offer more detail?

#### Cervesa

Can you offer more detail?
What "more details" do you have in mind?

#### Woody

I thought that friction opposed the direction of the motion
It is opposed to the motion that would otherwise happen if the friction was not there.
The bank is only providing a modest lateral force,
the rest is coming from the friction of the tires steering the car round the turn.

Another question which might have been asked, which could illuminate the issue, would be:
what is the maximum speed if the coefficient of friction were zero?
(the answer is much slower than with the friction).

Cervesa and studiot