1. Mechanical Advantage How much does an inclined plane, screw, wedge, pulley or lever really help you?

2. Designers of physical systems know from experience that there are many ways to perform the same task There job is to find the MOST efficient They are looking to find the tool that converts a small input into a much larger output.

3. Mechanical Advantage (MA): the ratio of output force to input force of a given machine

4. MA has NO units – it is just a comparison/ratio When input and output forces are the same, the MA is 1. When a machine has an MA GREATER than 1, this generally means it will make tasks easier and faster to accomplish.

5. Question: is it possible to have a mechanical advantage LESS than one??? Is there ever a time when the input force is GREATER than the output force….and we designed it that way?!

6. Our fist look at scientific formulas! Levers: MA = effort arm length load arm length Pulleys: MA = input distance output distance

7. Let’s try one together… 1.A wheelbarrow has an effort arm 120 cm long and a load arm 40 cm long. What is the mechanical advantage?

8. Check your learning! 1.Find the mechanical advantage of a wheelbarrow with an effort arm that is 1.8 m long and a load arm that is 0.50 m long. 2.To lift a load 5 cm with a pulley system, 15 cm of string has to be pulled. What is the MA? 3.What is the mechanical advantage of a pulley system if 4 m of string had to be pulled to lift a load a height of 1 m?