1. Systems In Action Mechanical Advantage
When Chuck Norris uses a simple machine, there is no mechanical advantage ... it’s mechanical DOMINATION!
Systems In Action
Mechanical Advantage

2. Mechanical Advantage – What is It?
When a machine turns a small input force into a larger output force, we say that 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 has no units, it is simply a
comparison ratio.

3. Mechanical Advantage – Ideal Vs Actual?
Ideal Mechanical Advantage – The mechanical advantage if all of the input force is converted into output force.
This is never possible in real-life situations.
Used for estimation purposes when you don’t know the measured output and input forces.
Two ways to calculate ideal mechanical advantage: 1/ 2/

4. Mechanical Advantage – Ideal Vs Actual?
Actual Mechanical Advantage – The mechanical advantage that actually occurs between input and output forces.
This is the mechanical advantage in real-life situations.
Equal to ideal mechanical advantage minus force lost (friction, slippage, distortion etc.)
Need to measure the forces involved.
To calculate actual mechanical advantage:

5. Mechanical Advantage – Levers
If you know the input force (effort) and output force (load), you can calculate the actual mechanical advantage. If not, you need to rely on estimating the ideal mechanical advantage.
Problem 1
The wheelbarrow in the picture has an effort arm 120cm long and a load arm 40cm long. What is its mechanical advantage?
Problem 2
Imagine that you are lifting a patio stone using a pry bar as a lever (picture). If the input force applied is measured as 25N and the output force is measured as 250N, then what is the mechanical advantage?

6. Mechanical Advantage – Levers
Problem 1
The wheelbarrow in
the picture has an
effort arm 120cm
long and a load arm
40cm long. What is
its mechanical
advantage?
Given: Effort arm length = 120cm
Load arm length = 40cm
Need: Mechanical Advantage (MA)
Solution:
Problem 2
Imagine that you are lifting
a patio stone using a pry
bar as a lever (picture). If
the input force applied is
measured as 25N and the
output force is measured
as 250N, then what is the
mechanical advantage?
Given: Measured Input Force = 25N
Measured Output Force = 250N
Therefore, this wheelbarrow has an ideal mechanical advantage of 3.
Therefore, this lever has an actual mechanical advantage of 10.

7. Homework ... Sorry.
In your own words, 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 0.6N is required to lift a rock of 36 N, what is the actual MA? Show your calculations.
A wheelbarrow has an effort arm that is 1.8m long and a load arm that is 0.50m long. What is the mechanical advantage of the wheelbarrow?
What parts of a pulley system will cause the actual MA to be less than the ideal MA?