What is this formula being used to calculate drag force?

In summary: Velocity-vd)/delta)) %B2/mfor i = 2:1000 positionX(i) = positionX(i-1) + initialVelocityX * timeStep positionY(i) = positionY(i-1) + initialVelocityY * timeStep dragForce = Bm * sqrt(initialVelocityX^2 + initialVelocityY^2) initialVelocityY = initialVelocityY + gravity * timeStep + (dragForce * initialVelocityY * timeStep) initialVelocityX = initialVelocityX + (dragForce * initialVelocityX * timeStep) %initialVelocity = sqrt(initialVelocityX^2 + initialVelocityY^
  • #36
@haruspex , I stand corrected. After looking at your equations, I think that you are correct that a headwind should decrease the maximum height of the ball's trajectory (I still need to get it clear in my mind.) I think that is the main issue of relevance to this thread.

The following issues are side issues to the OP and I am afraid that we may be hijacking this thread. But here are some final thoughts on my part.
haruspex said:
Yes.

What turn? The bike still goes in a straight line, and the front wheel still points straight ahead.
The steering geometry of a bicycle, and much more so of a motorcycle, includes a head tube angle, rake and trail that applies a torque to the front wheel when it is leaned into the wind.
The lateral static friction at the road contact counters the lateral component of the drag, while the net torque from those two is balanced by the torque from the gravitation/normal force pair.
A rolling tire does not have the usual lateral static friction. Because of tread distortion, the tire can move laterally as long as it is rolling. In order to travel in a straight line without lateral movement of the vehicle, a rolling tire must point to oppose the lateral movement.
I downloaded the NASA baseball applet, but I can't get it to work. It puts up a page with a banner naming the applet etc., but the rest of the page is blank. Tried it with both Google Chrome and IE.
I have never used it. I see that they say it is a beta test version and that PC security software may stop it from running. I don't really know anything about it.
 
Physics news on Phys.org
  • #37
FactChecker said:
The steering geometry of a bicycle, and much more so of a motorcycle, includes a head tube angle, rake and trail that applies a torque to the front wheel when it is leaned into the wind.
Sure, but the cyclist applies a static torque to the handlebars to stop the wheel turning. Muscle dynamics apart, no work done.
FactChecker said:
A rolling tire does not have the usual lateral static friction. Because of tread distortion, the tire can move laterally as long as it is rolling. In order to travel in a straight line without lateral movement of the vehicle, a rolling tire must point to oppose the lateral movement.
True, that will add a bit more to the load on the cyclist. But I maintain that the crosswind would still slow the cyclist even if that tendency to creep were balanced by, e.g., camber.
Indeed, this "creep load" would also arise on road that is cambered more than required for the cyclist's speed and no crosswind. Can't say I've ever noticed that making for harder work.
 
Last edited:
Back
Top