2. Simple Machines Device that makes doing work easier is a machine
Machines increase applied force and/or change direction of applied force to make work easier

3. Effort and Resistance Force applied to machine is effort force
Resistance force – force applied by machine to overcome resistance

4. Energy and Simple Machines
Amount of energy the machine transfers to the object cannot be greater than the amount of energy transferred to the machine

5. Energy and Simple Machines
An ideal machine with no friction would have the same input work and output work
Some energy transferred is changed to heat due to friction

6. Mechanical Advantage
The number of times a machine multiplies the effort force.
MA = Resistance Force
Effort Force

7. Efficiency W out x 100 Efficiency = in
Measure of how much of the work put into a machine is changed into useful output work by the machine.
Efficiency =
x 100
out W in

8. What force is it that opposes this motion?
Efficiency
The efficiency of machines can be determined by using a simple formula found on the formula chart.
Machines are always less than 100% efficient because of the force that opposes motion between the parts of the machine.
What force is it that opposes this motion?
Friction opposes the motion in the machines. Friction converts the machine’s work into heat. 8