Calculating Mechanical Advantage

Question

A bar sits on top of a brown triangle with a black weight at the left end and a finger pushing on the bar at the right end. Dotted lines run above and parallel with the bar and vertically from the above dotted line to the center of the weight, the point where the triangle meets the bar, and the finger. The distance from the center of the weight to the point of the triangle is labeled 2 meters. The distance from the point of the triangle to the finger is labeled 5 meters.

For the lever shown, a = 5 m and b = 2 m. What is the mechanical advantage of the lever?

Answer 1

To calculate the mechanical advantage (MA) of a lever, you can use the formula:

$$MA=\frac{a}{b}$$

where:

• $a$ is the distance from the point of applied force (the finger) to the fulcrum (the triangle), and
• $b$ is the distance from the fulcrum to the point where the load (the weight) is applied.

From your description:

• $a=5,\text{m}$ (the distance from the finger to the triangle),
• $b=2,\text{m}$ (the distance from the triangle to the center of the weight).

Plugging these values into the formula gives:

$$MA=\frac{5,\text{m}}{2,\text{m}}=2.5$$

Thus, the mechanical advantage of the lever is 2.5.