The Friction Oscillator

t

10

μ

k

0.5

W

10.

L

1.

x(0)

-0.25

x'(0)

0.25

The friction oscillator mechanism consists of a rod moving horizontally over two disks separated by a distance

2L

; the disks spin in opposite directions, providing a net kinetic friction with effective coefficient

μ

k

. Kinetic friction (shown in green) is proportional to the weight

W

. The rod moves a distance

x

because the components of normal forces (in brown) are changing.