An engine drives the line shaft through a belt of thickness t. If d1 and d2 are the diameter of the follower and driver respectively, the velocity ratio is
1
\(\rm \frac{d_1}{d_2}\)
2
\(\rm \frac{d_1-t}{d_2-t}\)
3
\(\rm \frac{d_1+t}{d_2+t}\)
4
\(\rm \frac{d_2+t}{d_1+t}\)