What is the velocity ratio for a slip in the belt drive system?

A

$$\frac{N_1}{N_2} = \frac{d_1 + t}{d_2 + t}\left(1 - \frac{s}{100}\right)$$

B

$$\frac{N_2}{N_1} = \frac{d_1 + t}{d_2 + t}\left(1 - \frac{s}{100}\right)$$

C

$$\frac{N_2}{N_1} = \frac{d_1 - t}{d_2 + t}\left(1 - \frac{s}{100}\right)$$

D

$$\frac{N_2}{N_1} = \frac{d_2 + t}{d_1 + t}\left(1 - \frac{s}{100}\right)$$