Mechanics > Rotational Dynamics > Rotational Inertia DCS# 1Q10.30 v. 2

RACING DISKS VARIATION

 

  APPARATUS
center-weighted and asymmetric racing disks
202-15-E5
hinged board or ramp
202-15-D
C clamps 202-01-D6
wooden box 101 aisle
box of sand covered with cloth or foam end stop
101-14-E

DESCRIPTION
This is a variation on the center-weighted vs perimeter-weighted racing cylinders; in this case, the cylinder with the larger rotational inertia about its rotation axis wins.  These two cylinders have equal masses but one is center-weighted and the other edge-weighted.  It is possible for the edge-weighted cylinder to win the race if it starts from the same height but with its center of mass higher than that of the symmetric cylinder, provided the ramp is not too long and the cylinders roll without slipping.  You can also adjust the ramp angle and initial orientation of the asymmetric cylinder so that it rolls up the ramp.

NOTES
Prop the board on a box and clamp the hinged piece of metal to the table top.

Mark the release height on the ramp from which the cylinders will land in the sandbox.

The o-rings are needed so the cylinders roll without slipping.

REFERENCE

Am. J. Phys., Vol. 73, No. 10, October 2005.