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a cooling fan is turned off when it is running at 850rev/min. it turns 1250revolution before it comes to a stop . what was the fan angular acceleration, assume constant ...How long did it take the fan to come to a complete stop |
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Answer» cooling fan is turned off when it is running at 850rev/min. It turns 1250 revolution before it COMES to a STOP. To find:What was the fan angular acceleration, ASSUME constant ...How long did it TAKE the fan to come to a complete stopSolution:From given, we have,wi = 850 rev/min= 850 rev/min × 2π rad/1 rev × 1 min/60 s∴ wi = 89.012 rad/swf = 0 rad/sΔθ = 1250 rev= 1250 rev × 2π rad/1 rev∴ Δθ = 7853.975 radWhat was the fan's angular acceleration, assumed constant?wf² = wi² + 2αΔθ α = (wf² - wi²)/2Δθ= (0² - 89.012²)/(2 × 7853.975) = -0.504 rad/s²∴ The angular acceleration α = -0.504 rad/s²How long did it take the fan to come to a complete stop?wf = wi + αtt = (wf - wi)/α= (0 - 89.012)/(-0.504)= 176.61 s∴ The time taken by the fan to come to a complete stop t = 176.61 s |
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