Basic Formula: 
IMA = E / R 
* This is going to sound confusing since
each simple machine has their own formula, but they all boil down
to: Effort / Resistance 
IMA = Ideal Mechanical
Advantage 
E = effort 
R = Resistance 


Units: 
IMA is a multiplier.
Meaning it represents how much the machine will multiply the force which
is put into it. It, therefore, has no unit and would be written
like: 3. This means that whatever amount of work is put into
the machine, you will get 3 times the work out. 

Effort will usually be a
distance: cm, m 

Resistance will also usually be
a distance although it needs to be the same unit as the effort so we
compare apples to apples. :) 
These problems are a bit
different than any of the others we have done before. (Many students
think these are easier since there are not any units involved.) There are
6 types of simple machines, four of them have distinct formulas to
calculate IMA. They are all based on the idea of E/R, but you have
to figure out what the Effort is and what the Resistance is. This
page has all the formulas for the different machines. Once you look
at the formulas, if you would like to check out some sample problems, click
on this link: <IMA
sample problems> 


Formulas: 

IMA of a lever: 
IMA= length of the effort arm / length of
the resistance arm 
IMA of a Wheel and axle: 
IMA= radius of the wheel (larger) / radius
of the axle (smaller wheel) 
IMA of a inclined plane: 
IMA= length of the slope/height of the
slope 
IMA of a pulley: 
The IMA is not a formula but a counting of
the number of Ropes that support the weight. (see page 191 in your book
for illustrations of this) 


