GATE 2016 ME (ME2) – Question 19
The forces F1 and F2 in a brake band and the direction of rotation of the drum are as shown in the figure. The coefficient of friction is 0.25. The angle of wrap is 3π /2 radians. It is given that R = 1 m and F2 = 1 N. The torque (in N-m) exerted on the drum is _________
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Show answer and explanation
Correct answer: 2.2 to 2.3
Explanation
At limiting friction, tight-to-slack tension ratio is exp(μθ)=exp(0.25·3π/2). For the shown rotation F1 is tight and F2=1N is slack. Thus F1≈3.248N and braking torque=(F1−F2)R≈**2.248N·m**. Wrap angle is used in radians.