1 September, 01:25

# Microwave ovens rotate at a rate of about 6 rev/min. what is this in revolutions per second? what is the angular velocity in radians per second

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1. 1 September, 04:06
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With some careful thinking you can see how to get the answer right away!

there are 60 seconds in a minute, so divide the 6rev/min by 60 to get rev/sec.

Then the second bit requires you to already know what a 'radian' is. This is kind of neat but definitely something you won't "just know".

Radians are an idea, rather than an actual thing. They can be described as this: 1 radian = the length of the radius wrapped around the circumference (the outline) of the circle. The radius of a circle goes around the circumference exactly 2π times. pi = 3.14, so 2π = 6.28, which is where π actually comes from! neat imo.

So this means that in 1 minute the microwave rotates through 6 x 2π radians. So now we have the total number of radians, simply divide "6 x 2π" by 60 like we did last time to get radians per second.

The equation looks like this:

(6 x (2 x 3.14)) / 60

or

(6 x 6.28) / 60

or

37.68 / 60