Question

When does a lever act as (a) a force multiplier, (b) a speed multiplier? Mention the corresponding class o lever. Can a machine act as a force multiplier and a speed multiplier simultaneously? $\left[6\text{marks}\right]$

Answer 1

(a) A machine acts as a force multiplier when the effort arm is longer than the load arm. The mechanical advantage of such machines is greater than 1. This property generally belongs to class 2 levers.
$\left[2\text{marks}\right]$

(b) A machine acts a speed multiplier when the effort arm is shorter than the load arm. The mechanical advantage of such machines is less than 1. This property generally belongs to class 3 levers.
$\left[2\text{marks}\right]$

It is not possible for a machine to act as a force multiplier and speed multiplier simultaneously. This is because machines which are force multipliers cannot gain in speed and vice-versa.
$\left[2\text{marks}\right]$