1. What is the mechanical advantage of a machine?

2. Mechanical Advantage Simple machines can make tasks easier.
A simple machine turns a small input force into a larger output force.
The machine gives us a mechanical advantage.
Mechanical advantage (MA) is the ratio of the output force to the input force (for example, the output force divided by the input force).
MA = output force
input force
When the input and output forces are the same, the mechanical advantage is one.
Machines with a mechanical advantage greater than one generally make tasks easier and faster to accomplish.

3. Mechanical Advantage
Imagine a hammer pulling a nail out of a piece of wood.
Imagine that hammer with
Input force = 3 N
Output force = 45 N
Use the formula for mechanical advantage to calculate the MA of the hammer.
output force N
input force N
The hammer has a mechanical advantage of 15. That means the output force is 15 times larger than the input force.
MA = = = 15

4. Finding the Mechanical Advantage of a Lever
One way of estimating the mechanical advantage of a lever is to compare the length of the effort arm with the length of the load arm.
The formula for mechanical advantage in this case is
MA = effort arm length
load arm length

5. The ideal mechanical advantage is what the mechanical advantage would be if all of the input force could be converted into an output force.
However, this is never possible in real-world applications.
Actual mechanical advantage is the mechanical advantage that actually occurs.
It is the ideal mechanical advantage minus any force lost to factors such as internal friction, slippage, and distortion.

10. CHECK YOUR LEARNING What is the meaning of “mechanical advantage”?
If an output force is five times larger than an input force, what is the mechanical advantage?
If an input of 0.6 N is required to lift a rock of 36 N, what is the actual mechanical advantage? Show your calculations.
The mechanical advantage of a class 3 lever will always be less than 1. Explain why.
If there is no mechanical advantage to class 3 levers, why are they considered useful?
What parts of a pulley system will cause the actual mechanical advantage to be less than the ideal mechanical advantage?