1. Simple Machines and Mechanical Advantage

2. What is a Machine? Definition:
any device that makes work easier by changing a force
Work is done whenever a force moves an object over a distance

3. How do machines make work easier?
Machines change how the work is done by
Increasing the amount of force that is applied
Increasing the distance over which the force is applied
Changing the direction in which the force is applied

4. Increasing force?
The machine applies more force than the user but over a shorter distance

5. Increasing Distance
The machine increases the distance over which the force is applied, but it reduces the strength of the force

6. Changing the direction of force
The machine changes the direction of the force applied by the user

7. Simple vs. Compound Machines
There are 6 types of simple machines
Inclined plane
Lever
Pulley
Wheel and Axle
Screw
Wedge
Compound machines combine two or more simple machines

8. Measuring the change in force
How much a machine changes the input force is called its mechanical advantage
Remember
Input force = force you place on machine
Output force = force machine places on object
Two types:
Actual
Ideal

9. Actual Mechanical Advantage
Takes into account the amount of the input force that is used to overcome friction
Difficult to measure input and output forces

10. Ideal Mechanical Advantage
Uses input and output distance instead of force
Does not take into account friction and will always be greater than actual mechanical advantage

11. Practice
Calculate the ideal mechanical advantage for the incline plane shown above.

12. Practice
A force of 200 N is applied to a machine in order to lift a 1,000 N load. What is the mechanical advantage of the machine?
A machine is designed to push an object with a weight of 12N. If the input force for the machine is set at 4 N, what is the mechanical advantage of the machine?

13. Practice
An input force of 35 N is applied to a machine with a mechanical advantage of What is the size of the load this machine could lift (how large is the output force)?
A machine is required to produce an output force of 600 N. If the machine has a mechanical advantage of 6, what input force must be applied to the machine?