Re: Conrod force/acceleration

["Jouko Haapanen" <joukoh@vtoy.fi>]

-----Original Message-----
From: Luis Marques <marques@rtis.ray.com>


  --snip--
>
>OK, I have tried to stay out of this very hard, but since there is still
>a lot of confusion out there about velocity and acceleration and all
>that, I'll try to explain.  Although it may not make sense at first,
>anyone who has taken a calculus course will be able tell you that
>acceleration is simply the derivative of velocity, or in simpler words,
>that acceleration is a measure of how fast the speed is changing.  As
>such, the instantaneous velocity doesn't tell you anything about
>acceleration.  It is how fast the speed is changing that tells you the
>acceleration of an object.  So the fact that at an instant in time a
>piston has zero velocity doesn't imply that it has zero acceleration.
>
>For an engine at constant RPM, if one were to plot the velocity of a
>piston as a function of time it will look very close to a sine wave. 
>The acceleration, being the derivative of velocity, will look like a
>sine wave offset by 90 degrees (cosine wave).  So the piston velocity
>will be 0 at the very top and the very bottom of it's travel while the
>acceleration is at maximum, and the acceleration will be zero when the
>piston is at the middle of it's upwards or downward travel with maximum
>speed.
>


THANK YOU!!!!
For the ones still grasping at this one, try Calculus 101.  ;^)


Jouko "can we drop this thread now" Haapanen
Pori, Finland