Simple Machines: Pulley Lab

• In this weeks lab, we made a pulley system to figure out how simple machines help us in our everyday life. But before we made anything, we measured how much force it takes to manually life a 200 gram (.2kg) brass mass 10 cm or .1 meters. To life the brass mass .1 meters, it takes 2 Newtons of force. 

• THEN we made the double pulley machine that is in the picture below. We used a ruler to measure 10cm from the surface of the table, and an electronic force probe to get a very specific reading on how much force is exerted while using a simple machine. 

• When we pulled the force probe down until the brass mass was 10 cm off the table, the probe read that it only took .9 Newtons! That's weird though isn't it? Just by using a simple machine, the amount of force needed was cut just about in half. How is this possible?

The Trade-Off

• Instead of just using your hand to pick up the brass mass off of the table and using 2 Newtons, the simple machine only uses .9 Newtons but also needed 20 centimeters of string in order or get the other string that had the brass mass attached to it off of the table. 

• SO the trade-off for using a simple machine rather than manual force is that you use less force over a greater area of distance. Meaning, if you increase the distance, you can decrease the force.

• Taking a look at our whiteboard, we also were able to figure out tat distance and force when represented by numbers, are reciprocals or inversely proportional. 

• Although it is not super clearly represented in our chart, the shaded portion of both squares, or their area's are the same. This shaded area in a force vs. distance graph is called the ENERGY (J). No matter wether one uses their manual force or the force of a simple machine, the two processes will both have the same energy.

• We call the energy transferred over a distance WORK (J). 

• Using the knowledge of our graphed date and the general equation of the area of a surface helped us derive our next big physics equation which i have illustrated below: 

• A real-world connection of the idea of this whole experiment would be the use of curtain drawstrings. instead of applying force directly to the curtains and trying to get them perfectly to their designated sides, one may use a draw string instead (like the ones we have at SI) to make their lives easier because they wont have to use as much force. 

 <-- MORE FORCE

                                       LESS FORCE -->

SAME ENERGY!