Question

A friction clutch is in the form of a frustum of a cone, the diameter of the ends being 32cm and 20cm and length 8cm. Find its bearing surface (lateral surface area).

• A. 817.14 cm²
• B. 820.48 cm²
• C. 884.00 cm²
• D. 739.29 cm²

Answer 1

The correct option is C

884.00 cm²

Let ABB'A' be the friction clutch of slant height l cm

$r_1$=16 cm, $r_2$ =10 cm, and h = 8 cm
l = 10 cm, bearing surface = lateral surface
$A=\pi \times (R+r)l$
A = 3.14 $\times$ (16+10)10
= 884 cm