# Physics

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n early method of measuring the speed of light makes use of a rotating slotted wheel. A beam of light passes through one of the slots at the outside edge of the wheel, travels to a distant mirror, and returns to the wheel just in time to pass through the next slot in the wheel. One such slotted wheel has a radius of 6.0 cm and 850 slots at its edge. Measurements taken when the mirror was l = 500 m from the wheel indicated a speed of light of 3.0 105 km/s.

(a) What was the (constant) angular speed of the wheel?

(b) What was the linear speed of a point on the edge of the wheel?
m/s

• Physics - ,

I will be happy to critique your work.

• Physics - ,

Okay. So first for part b I know the formula I'm going to need is v=wr. That will relate the linear speed to the angular speed and we are given the radius. I'm still a little stuck though on the angular speed. I found the circumference of the wheel to be 10pi cm, and the space in between each slit to equal pi/50 cm (not sureif this is helpful). So should I find out the time it takes each light particle to get to the next slot using the speed of light given, then divide the distance between each slot byt hat time to get the angular speed?