Question

The driving wheel of a gear system is of radius 1 cm and it has 8 teeth. For twelve rotations of the driving wheel, the driven wheel makes one rotation. Find the radius of the driven wheel.

• A. 2 cm
• B. 4 cm
• C. 8 cm
• D. 12 cm

Answer 1

The correct option is D

12 cm

Radius of the driving wheel, r${}_A$​ = 1 cm

Number of teeth of driving wheel, N${}_A$​ = 8

Number of rotations of wheel = 1

Radius of driven wheel = r${}_B$​

Number of rotations (n${}_a$​) = 12

Number of rotations (n${}_b$​) = 1

$\frac{n_a}{n_b}$ = $\frac{r_B}{r_A}$

$\Rightarrow$ $\frac{12}{1}$ = $\frac{r_B}{1}$

r${}_B$​ = 12 cm