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

RACING DISKS


APPARATUS
box of cylinders, hoops, and spheres 202-15-E5
hinged board 202-15-D
C clamps 202-01-D6
wooden box 101 aisle
end stop
101-14-C
ruler
101-05-C

DESCRIPTION
Roll various pairs of objects simultaneously down the inclined plane to show which ones reach the bottom first.

Roll different solid spheres to show that velocity is independent of mass and radius.

Show that velocity depends on mass distribution by rolling two non-uniform cylinders of the same mass and radius down the incline.  One cylinder has a lead core and wooden shell, the other has a wooden core and lead shell.

Race the hoop, cylinder, and sphere of the same radius.

Other objects to race include the water-filled (or chicken-broth-filled) cylinder, fluid-filled sphere, "frictionless" air puck, and the asymmetric disk.

 
NOTES

Prop the board on the box and clamp the end stop over the hinged piece of metal and to the cart.

The ruler can be used to hold the objects in place on the ramp; this helps in releasing them at the same time with no initial velocity.

Setup shown with camera and side bumpers:

racing disks