The velocity factor for precision metallic gears cut with high accuracy and operating at velocities up to 20 m/s is equal to
A. $$\frac{{0.75}}{{0.75 + \sqrt {\text{v}} }}$$
B. $$\frac{3}{{3 + {\text{v}}}}$$
C. $$\frac{{4.5}}{{4.5 + {\text{v}}}}$$
D. $$\frac{6}{{6 + {\text{v}}}}$$
Answer: Option A

4.5/4.5+ v for careful cutting of gear and it's velocity up to 12.5 m/s.
6/6+v for accurate and velocity 20 m/s 0.75/0.75+v for precision and velocity up to 20 m/s (0.75/1+v )+ 0.25 for non metal gears.
Velocity factor.
3/(3+v): v
For mettalic D is the Correct answer.
No metallica option a is correct