Question

A pair of spur gears with module 5 mm and a center distance of 450 mm is used for a speed reduction of 5 : 1. The number of teeth on pinion is

Answer 1

$\frac{N_P}{N_G}=5=\frac{T_G}{T_P}$
$T_G=5T_P$
$C=\frac{m}{2}(T_P+T_G)$
$T_P+T_G=\frac{2C}{m}=\frac{2\times 450}{5}=180$
or $6T_P=180$
or $T_P=30$