Math Skills
Calculating IMA
A woman drives her car up onto wheel ramps to perform some repairs. If she drives a distance of 1.8 meters along the ramp to raise the car 0.3 meter, what is the ideal mechanical advantage (IMA) of the wheel ramps?
Read and Understand
What information are you given?
Input distance = 1.8 m
Output distance = 0.3 m
Plan and Solve
What unknown are you trying to calculate?
IMA = ?
What formula contains the given quantities and the unknown?
Replace each variable with its known value and solve.
Look Back and Check
Is your answer reasonable?
The IMA must be greater than 1 because the input distance is greater than the output distance. The calculated IMA of 6 seems reasonable.
Math Practice
A student working in a grocery store after school pushes several grocery carts together along a ramp. The ramp is 3 meters long and rises 0.5 meter. What is the ideal mechanical advantage of the ramp?
A construction worker moves a crowbar through a distance of 0.50 m to lift a load 0.05 m off of the ground. What is the IMA of the crowbar?
The IMA of a simple machine is 2.5. If the output distance of the machine is 1.0 m, what is the input distance?
Efficiency
Because some of the work input to a machine is always used to overcome friction, the work output of a machine is always less than the work input. The percentage of the work input that becomes work output is the efficiency of a machine. 
Because there is always some friction, the efficiency of any machine is always less than 100 percent.
Efficiency
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