Re: MBL, was Re: Air resistance

[Steve Luzader <sluzader@fre.fsu.umd.edu>]

I've done the kind of experiment John describes below, and as he
notes it 
worked very nicely.  Even the uninitiated students could tell that the
plotted 
distance vs time graphs weren't exactly parabolic because of the
different 
accelerations when the toy cars they were using rolled up and then down
the 
ramp.  As far as effects of air resistance on balls is concerned, I have
gotten 
some very nice data using a motion detector mounted on a tall pole
looking 
down towards the floor observing a ball bouncing under it.  Even in this
case 
one can tell that the acceleration of a low density ball is different
for 
upward and downward motion.  (I'll add that the absolute best air
resistance 
data I've gotten in student projects is by videotaping the ball and
analyzing 
the tape frame by frame.)

Steve Luzader

-- 
Stephen Luzader
Frostburg State University
Frostburg, MD
http://antoine.fsu.umd.edu/phys/luzader

John Gastineau wrote:
>

> However, using a cart and a dynamics cart track, you can get very nice data
> with little set up trouble. You can easily get velocity and acceleration
> data of good quality by tilting a desk, using a cart on the desktop, and
> placing the motion detector right on the desk surface. Such data are good
> enough to detect the slight difference in acceleration as the cart rolls up
> the slope compared to the roll down slope. Good physics, there.
>
> JEG