Question

In a band brake the ratio of tight side band tension to the tension on the slack side is $3$. If the angle of overlap of band on the drum is ${180}^{\circ }$ the coefficient of friction required between drum and the band is

• A. $0.20$
• B. $0.25$
• C. $0.30$
• D. $0.35$

Answer 1

The correct option is D $0.35$

Given date :
$\frac{T_1}{T_2}=3,\theta ={180}^{\circ }=\frac{\pi \times 180}{180}=\pi rad$

$\frac{T_1}{T_2}=e^{\mu \theta }\Rightarrow 3=e^{\mu \pi }$

$\Rightarrow \ln 3=\mu \pi$

$\Rightarrow \mu =0.345=0.35$