Question

What is always true of the mechanical advantage of a third class lever? Of a second? Of a first?

Answer 1

Class 3 lever:

A third class lever will always have a mechanical advantage of less than 1

So therefore do not give any mechanical advantage

Class 2 lever:

Mechanical advantage of Class two levers is usually greater than one.

It is because the overall length of the Effort Arm is higher than the overall length of Load Arm.

Class 1 lever:

The mechanical advantage of a first class lever depends upon the placement of the fulcrum. If the fulcrum is closer to the load than to the input force, the lever has a MA > 1.

If the fulcrum is exactly in the middle of the load and the input force, the MA = 1.

If the fulcrum is closer to the input force than to the load, the lever's MA < 1.