# Homework Help: Normal force on horizontal plane

1. Sep 21, 2008

### Niles

1. The problem statement, all variables and given/known data
Lets say that a person called A rides his motorcycle. When this person turns, he tilts his motorcycle on a horizontal road. Is the normal force still normal to the surface or does it point in the same direction as the person sitting on the bike?

3. The attempt at a solution
Ok, here's my line of thought: I think it is still perpendicular to the horizontal road, because if it wasn't, then he would have a net force pointing inwards (not counting in centripetal force).

What I mean is: The Tower of Pisa doesn't accelerate just because it titls - am I correct?

2. Sep 21, 2008

### Staff: Mentor

Well, by definition the normal force is perpendicular to the surface. I suppose you mean: Does the net force of the ground (normal plus friction) on the bike point normal to the surface? It better not, since that force must provide the centripetal force to make the turn.
While the Tower of Pisa isn't accelerating, the motorcycle is.

3. Sep 21, 2008

### Niles

I actually did mean whether the normal force on the tilted bike is normal to the plane or follows the biker.

But yes; as you say, it's "normal force" - so always normal to the surface, no matter if the object is tilted or not.