The spin cycles of a washing machine have two angular speeds, 423 rev/min and 640 rev/min. The internal diameter of the drum is 0.470 m. (a) What is the ratio of the maximum radial force on the laundry for the higher angular speed to that tor the lower speed? (b) What is the ratio of the maximum tangential speed of the laundry for the higher angular speed to that for the lower speed? (c) Find the laundry’s maximum tangential speed and the maximum radial acceleration, in terms of ?g.

Solution to 29E Step 1 First angular speed of washing machine =4231rev/min Second angular speed of washing machine =640 r2v/min Diameter of drum=0.470m Radius of the drum =0.235m Step 2 2 a = r 2 F radial ma = m r 2 F radial ma = m r1…………………………………………..(1) 2 F radialma = m r2………………………………………….(2) F radial m 12 = 2 Fradial m2r F 2 radia= 1 Fradial 22 2 F radial (423) Fradial (640) F radial Fradial 0.436 Fradial F = 2.29 radial Step 3 (b)Ratio of tangential speeds of two different angular speeds. v = r v 1 r1…………………………………………………………(3) v 2 r2………………………………………………………….(4) (4)/(3) v2 2r = v1 1r v 2 = 2 v1 1 v 2 = 1.51 v1