Physics help me!

Question

The blades of a windmill are travelling in circular motion for 5revolutions in 20seconds. The blades have a length of 9m from the center to the tip.

a) What is the frequency of this motion in RPM(revolutions per min.)?

b) How much is the speed at the tip of the blades?

 

help me

Answer 1

  

Given

Length of the blade r = 9 m

Speed of the blade N =( 5/20) RPS

a)

Calculate the frequency in RPM .

f = 60N

  =(60)(5/20)

   = 15 RPM

 

Therefore, the frequency in RPM is 15 RPM

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b)

Calculate speed of the blade at tip .

v = rω

  = (9)(2 π (15))/60

   =14.14 m/s

 

Therefore, the speed of the blade is 14.14 m/s