What is the length of a belt with diameter $$d_1$$ and $$d_2$$ and at distance x apart, is connected by means of an open belt drive?

A

$$\frac{\pi}{2}(d_1 + d_2)2x + \frac{(d_1 + d_ 2)^2}{4x}$$

B

$$\frac{\pi}{2}(d_1 - d_2)2x + \frac{(d_1 - d_ 2)^2}{4x}$$

C

$$\frac{\pi}{2}(d_1 + d_2)2x + \frac{(d_1 - d_ 2)^2}{4x}$$

D

$$\frac{\pi}{2}(d_1 - d_2)2x + \frac{(d_1 + d_ 2)^2}{4x}$$