# Spinning Force?

1. Sep 1, 2008

### pimpalicous

The other day, my professor mentioned projectiles have a force on them due to their spin. The example he gave is how a baseball curves because of the spin of a curve ball. What's the name of this force?

2. Sep 2, 2008

### Staff: Mentor

Probably just best to call it lift.

3. Sep 2, 2008

### FredGarvin

Magnus effect covers this in the general sense. It is not a name of a force though. Like Russ said, it probably is best to just call it lift or a side force depending on your frame of reference.

http://en.wikipedia.org/wiki/Magnus_effect

4. Sep 2, 2008

### rcgldr

Another description of Magnus Effect, based on detachment of air flow:

http://www.geocities.com/k_achutarao/MAGNUS/magnus.html

The force is an aerodynamic force. By definition, lift is the component of aerodynamic force perpendicular to the direction of travel (with air as the frame of reference), and drag is the component of aerodynamic force in the direction of travel. Regardless of the method used to create the aerodynamiic force, Newton's 3rd law applies, forces only exist in pairs. The aerodynamic force exerted by the air onto an object is coexistent with the object exerting an equal and opposite force to the air, and the air responds to the force exerted by the object according to Newton's 2nd law, force = mass times acceleration.

Last edited: Sep 2, 2008
5. Sep 2, 2008

### pimpalicous

Magnus effect! That's what he called it. I thought he said magnus force but I may have misheard him. Thanks!