Velocity Ratios and Speeds

Gear Velocity Ratios

Velocity ratios are calculated by dividing the driver gear by the driven gear. The driver gear or pulley is the one connected to the power - e.g. the pedals on a bicycle or the motor.
To calculate the speed of the driven gear - multiply the speed of the driver gear by the velocity ratio.
In all the questions the driver is on the left - the first gear wheel.

VR= 12/24 =1/2

VR=1/2 or 0.5
Driven speed =1000rpm so final speed = 1000 x 0.5 = 500rpm
All the questions are based on sprocket and chain systems but the calculations are exactly the same for gear trains.