The frictional torque transmitted in a flat collar bearing, considering uniform pressure, is (where r1 and r2 = External and internal radii of collar respectively)
A. $$\frac{1}{2}\mu {\text{W}}\left( {{{\text{r}}_1} + {{\text{r}}_2}} \right)$$
B. $$\frac{2}{3}\mu {\text{W}}\left( {{{\text{r}}_1} + {{\text{r}}_2}} \right)$$
C. $$\frac{1}{2}\mu {\text{W}}\left( {\frac{{{\text{r}}_1^3 - {\text{r}}_2^3}}{{{\text{r}}_1^2 - {\text{r}}_2^2}}} \right)$$
D. $$\frac{2}{3}\mu {\text{W}}\left( {\frac{{{\text{r}}_1^3 - {\text{r}}_2^3}}{{{\text{r}}_1^2 - {\text{r}}_2^2}}} \right)$$
Answer: Option D

me after reading this 4 month later. itna confusion kyo tha bhai.
nhi d hi hai sahi answer
the answer is a
the answer is b