Class I Levers

These types of levers, the fulcrum F is in between the effort E and the load L as shown in figure. Note that the fulcrum F need not be at the mid-point between the load L and the effort E. The load and effort is works in the same direction. In general the effort arm is greater than load arm.

In fig. AB is a class I leaver, F is fulcrum. Load L is hang from the point B. and an effort E apply from the point A. here AF is effort arm and BF is the load arm. Here,

Applied Effort x Effort Arm = Mass x Load Arm

E x AF = W x BF

M.A = W/E = AF / BF

Mechanical advantage of class I lever depends on the ratio of the length of effort arm and load arm.

• If effort arm is longer than load arm then mechanical advantage is greater 1. And in this case we can get maximum output by applying minimum effort. Handle of tube well.

• If effort arm is smaller than load arm then mechanical advantage is less than 1. And in this case we can get minimum output by applying maximum effort. Eg seesaw

• If effort arm is equal to the load arm then mechanical advantage is exactly 1. And in this case we can get no mechanical advantage. e.g. Weight machine