Cans On Inclined Plane - With And Without Water


To illustrate the effect of moment of inertia on rolling acceleration.


Tilting hospital cart, push broom, two cans, one mostly filled with water.

Setup Time

5 min.




Roll two identical cans from rest down an incline, where one is empty and the other is nearly filled with water. Q: Which gets to the bottom first, or is it a tie? A: The water-filled can reaches the bottom first. Due to its small viscosity,the rotation of the water is limited, and that can acts much like a body sliding without friction down the incline. Using the broom, give the two cans a push up the incline. Which can will roll higher up the incline?


PIRA 1Q10.50)