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10 months ago

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In the lab downstairs physics majors use a rotating mirror to measure the speed of light within a few percent of the actual valu

e they switch the mirror from rotating clockwise at 115 rad/s to counter clockwise at 115 rad/s over the course of 85 seconds. Assume constant angular acceleration.
QUESTION: how many revolutions does the rotating mirror go through when it gets to a 0 angular velocity along the way to new speed. SHOW WORKING OUT

1 answer:

iris [78.8K]10 months ago

7 0

The number of complete cycles the rotating mirror goes through before the angular velocity gets to zero is approximately 1166.8 revs

<h3>What is angular velocity?</h3>

Angular velocity is the ratio of the angle turned to the time taken.

The kinematic equation for angular velocity are presented as follows;

ω = ω₀ + α·t

θ = θ₀ + ω₀·t + 0.5·α·t²

Where;

θ₀ = The initial angle turned = 0

ω₀ = The initial angular velocity of the mirrors = 115 rad/s clockwise

α = The angular acceleration = (115 - (-115))rad/s/(85 s) = -46/17 m/s²

t = The duration of the motion;

When the angular velocity, ω is zero, we get;

0 = 115 - 46/17·t

t = 85/2

Which indicates;

θ = 0 + 115× (85/2) + 0.5×(46/17) ×(85/2)² = 7331.25

θ = 7331.25 radians

θ = 7331.25/(2×π) ≈ 1166.8 rev

The mirrors would have turned through approximately 1166.8 revolutions when the angular gets to zero

Learn more about angular velocity and acceleration here:

brainly.com/question/13014974

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