Name: _____________________________________________ Period: _______
Practice Calculating IMA, AMA and Efficiency
Ideal Mechanical Advantage of Inclined Planes
Mechanical advantage of an ideal machine (theoretical)
(IMA = Effort Distance)
Load (resistance) Distance
Actual Mechanical Advantage of Inclined Planes
Mechanical advantage of an actual machine
(AMA = Load Force)
Effort Force
Efficiency of Inclined Planes
(Efficiency = Output work
(load force x load distance)
X 100 = Percent
Input work
(effort force x effort distance)
Output work refers to the work the machine is doing, or another way to look at it – the amount of
work that would be required without the machine
Input work refers to the amount of work required because of using the machine
1. Draw a picture of an inclined plane.
2. In your diagram, place the following labels and/or values in the correct locations:
A. Load Distance = 12 meters
B. Load Force
= 22 Newton’s
C. Run
12m
22N
36m ef = 11N
Run
3. If you were to lift the load straight up without the machine (inclined plane) how much work would
you need to do? 264J _________________________. (Work = force x distance)
This value is known as the output work.
4. In your diagram, place the following label and value in the correct location:
A. Effort Distance = 36 meters
5.
What is the IMA (Ideal Mechanical Advantage) of the inclined plane? 36/12 = 3
In theory, this machine should reduce your effort by this many times.
6. In your diagram, place the following label and value in the correct location:
A. Effort Force
= 11 Newtons
7. What is the AMA (Actual Mechanical Advantage) of the inclined plane? 22 / 11 = 2
8. How much work was done to move the load along the incline? 36 x 11 = 396 J
This value is known as the input work.
9. How much more work was done to move the load up the inclined plane as opposed to lifting the
load straight up? 396 – 264 = 132 Joules
10. Why was the extra work needed?
Overcome friction
_______________________________________________________________________________
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11. Ultimately, it was more work to use the inclined plane. If it was more work, then why use it?
It reduced the amount of force
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12. What was traded off to make the effort easier? distance
13. Let’s look at this machines’ efficiency. How efficient is this machine? 67%.
14. Challenge: What is the ratio of AMA to IMA? 2:3 67
What is the ratio of output work to input work? (Determine GCF) 264: 396
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For 1, 2 and 3 below:
a. Circle and label the location of effort force (Ef), effort distance (Ed), load force (Lf) and load
distance (Ld)
b. Calculate IMA, AMA and the efficiency:
IMA = 2.4
AMA = 2
1.
Output work = 100
12m / 10n
Input work = 120
5m
Efficiency = 83%
20n
2.
24m / 60n
2m
500n
3.
78cm
7n
117cm
5n
IMA = 12
AMA = 8.3
Output work = 1000j
Input work = 1440j
Efficiency = 69%
IMA = 1.5
AMA = 1.4
Output work = 5.5
Input work = 5.85
Efficiency = 94%