A flywheel flows from 250rpm to 150rpm in 4.2 seconds. How many revolutions occur during this time

14 revolutions

Explanation:

Given that,

Initial angular velocity,

Final angular velocity,

Time, t = 4.2 seconds

We need to find the number of revolutions occur durung this time.

250 rpm = 26.17 rad/s

150 rpm = 15.70 rad/s

Let is angular acceleration. Using first equation to find it.

Now let us suppose that the number of revolutions are .

or

Hence, there are 14 revolutions.

The average speed during the slowdown is 200 RPM.

4.2 seconds is (4.2/60) = 0.07 minute.

(200 rev/minute)x(0.07 minute)= 14 revs

d.7.5cm is your answer

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

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