How To Understand Mechanical Advantage

HOW TO UNDERSTAND MECHANICAL ADVANTAGE

Mechanical comprehension tests are widely used during selection processes that involve technical jobs. Having an understanding of mechanical advantage is crucial to your success during the test.

You may find that some mechanical comprehension tests ask you to calculate the mechanical advantage of a simple pulley system.

Here’s an explanation of how mechanical advantage works when using a simple pulley system.

EXAMPLES OF SIMPLE PULLEY SYSTEMS

Mechanical pulley systems

EXAMPLES OF SIMPLE PULLEY SYSTEMS

If you study the three pulley systems above you will note that each system has both supporting ropes and non-supporting ropes. Supporting ropes are ones which, as the name suggests, support the load. Only the first two pulley systems have non-supporting ropes which I have indicated. The non-supporting ropes in the first two pulley systems above simply change the direction of the force.

To calculate the mechanical advantage in a moveable pulley system, we simply have to count the number of supporting ropes. Counting the supporting ropes in the pulley systems above, the mechanical advantage of each of system is, from left to right 2, 3, and 5.

In order to demonstrate further the concept of mechanical advantage using simple pulley systems, please try the following sample two questions to see how you get on.

Question 1
What is the mechanical advantage?

Simple pulley system

Q1. For this simple pulley system there is just one supporting rope. Therefore,
the mechanical advantage is 1.

Question 2
What is the mechanical advantage?

Simple pulley systems

Q2. In question 2 you will notice that the pulley is not attached directly to
the beam. This is known as a moveable pulley system whereby the pulley is
attached to the load/weight. When the rope is pulled up the weight/load will
also move up. You will notice that the weight is supported by both the rope
end attached to the upper beam and the end which will be held by the person.
Each side of the rope is now supporting the weight; therefore, each side
carries only half the weight. The mechanical advantage of this system is 2.

PRODUCTS THAT MAY BE OF INTEREST

 

Before you sit any mechanical comprehension test make sure you gain a full understanding of pulley systems, cogs and levels.

To learn how to pass mechanical comprehension tests we recommend you obtain our informative and detailed book on this type of test.