Arc Length & Area of a Sector

Formulas

Arc length:  s = rq , where is measured in radians

Area of a sector:  K = 1/2 r2q

The angular speed of a particle is q / t.

Problem: A phonograph record with diameter 12 inches turns at 33 1/3 rpm. Find the distance that a point on the rim travels in one minute.

33 1/3 = 100/3

C = 2pr  =  12p

100 rev   x   12p in  =   400p inches
  3  min        1 rev               1 min


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