In the open circuit the current can not flow from one end of the power source to the other. Because of this there is no current flow, and therefore the light does not turn on.
I think the situation is modeled by the scenario in the attached image. Some specific values seem to be missing (like the height of door
)...
The door forms a right triangles that satisfies

We also have

so if you happen to know the height of the door, you can solve for
and
.
is fixed, so

We can solve for the angular velocity
:

At the point when
and
ft/s, we get

I believe that fidget toys should not be brought back in school, reason being is because fidget spinners were originally made for students with example: Autism . Who actually needed them. Now that people who don't need them are buying them and playing with them in the classroom, it causes a complete distraction and is not being used for its original purpose whatsoever .
By tightening a string you are actually putting more stress on the string you are giving it a new frequency that isn't natural.
Hope this helps
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