In a lever, fulcrum is at one end at a distance of 30 cm from the load and effort is at the other end at a distance of 90 cm from the load. Find :

(a) the length of load arm,

(b) the length of effort arm, and

(c) the mechanical advantage of the lever.

Given,

Distance of fulcrum from the load = 30 cm

Distance between load and effort = 90 cm

(a) Length of load arm = Distance of fulcrum from the load = 30 cm

(b) Length of effort arm = Distance between load and effort + Length of load arm = 90 + 30 = 120 cm

(c) Mechanical advantage of a lever is :

$\text {Mechanical Advantage}=\dfrac{\text {Effort Arm}}{\text {Load Arm}}=\dfrac{120 \text { cm}}{30 \text { cm}}=4$