Mechanics:
Loop the Loop

PIRA Class: 1M40.20

Purpose:
To demonstrate conservation of energy and centripetal acceleration for a ball going through a vertical loop.

Description:
A white ball, if released high enough on the left side, will pass smoothly through the loop without falling off the track. If released too low, the ball will fall. There are lines on the track marking starting heights, these may or may not be correct - a good opportunity to discuss with students what happens in the demo that is not accounted for in the standard frictionless block calculation.

PEDAGOGY: Ask students how high they think you must release the ball in order for it to make it through the loop. Many students may predict that the ball should be released even with or slightly higher than the top of the loop. Demonstrate that this does not work (the ball falls) then calculate the correct starting height (diameter of the loop is 41 cm).

Optional: If you want to include the rotational kinetic energy of the ball, the ball's diameter is 4 cm.

Equipment:
Loop the loop track and ball

Location:
Shelf 145 (track), shelf 132 (ball)

Extras:
Solution to the loop-the-loop problem for a track with friction