An experimental automobile brake design works by pressing the fixed red annular plate agai...

An experimental automobile brake design works by pressing the fixed red annular plate against the rotating wheel. Suppose that μk = 0.65 and the force pressing the plate against the wheel is F = 2 kN.

(a) What couple is exerted on the wheel?

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(b) What percentage increase in the couple exerted on the wheel is obtained if the outer radius of the brake is increased from 90 mm to 100 mm?