Instructions
Photos above
show the apparatus for doing conservation of angular momentum demos.
If
you get the bicycle wheel spinning and start with its angular momentum
vector vertical, then flipping the wheel by 180 degrees about a
horizontal line through the center of the bearing hub will produce a
nice( counter ) rotation about a vertical axis of you and the stool.
Conservation of both the magnitude and the direction of angular momentum.
This
stool rotation can then be negated by another flip of the wheel.
Start a
person, who is holding hand weights, to rotating with her arms
extended.
Be sure
to only give a very modest linear speed to her extended hand,
less than 1 meter/s. Less than 20 RPM !!
Then
have the person pull the weights in close to her chest, to see a
dramatic increase in rotation rate. Conservation of magnitude of angular momentum.
Don't
let a person spin for more than a few seconds before stopping
them !!
SAFETY
NOTES:
1.Probably
best not to let long-haired students handle spinning wheel.
2.The new bike wheel may be spun up adequately by hand-slapping the rims.
3.You may also use the electric motor device to spin the wheel up.
4. Older
users (perhaps above 40) may need to worry about spinning too rapidly potentially causing damage in their eyes !! _________________________________________________________________________________________________________________________________
New Apparatus for Demo
We have
added :
1) a rotating stool
2) a new bike wheel (with brass air foil coverings over the spokes)
3) an electric motor on a dedicated metal base
4) an aluminum cylindrical disc on the motor shaft to spin the wheel up to speed.
The
new equipment is seen in the above two photos, residing in its home
storage space on the floor to the left of the door from the prep room
into SC4327.
This is the space formerly occupied by the retired dentist chair referred to above.
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