A block-brake shown below has a face width of 300 mm and

A block-brake shown below has a face width of 300 mm and a mean coefficient of friction of 0.25. For an activating force of 400 N, the braking torque in Nm is

Taking moment about A,
R_N × 200 = 400 × 600
⇒ R_N = 1200 N

∴ Braking torque T_B = μ.R_N ×	D	= 45 Nm
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