In class last week we again used our Lego mind-storm robotics but this time it was not a car but instead was hooked up to a pulley system.  The Robot’s sensors allowed us to record how much energy it’s battery used while lifting different weights.  we started off with a heavy amount and worked our way down.  our robots mechanical arm was connected to a string which ran to pulley.  We worked with partners and ran 3 tests each time with a different amount of weight.  The results clearly show that the more weight the robot lifted the more energy was discharged from the battery.  This experiment showed how energy is used to defy the forces of gravity.  The power from the battery was transferred into potential energy as the weight was lifted, some energy was lost however, when it was turned into heat.

a simple pulley rigged as it was during the experiment

The Results:

Run I           Run II         Run III

Mass:                            250g              200g             150g

Rotations:                    1155               1297              1186

Battery discharge:     27mv              19.3mv           14mv

speed:                           32.49rpm      77.70rpm      82.12rpm

Time:                            5.92s               2.78s              2.40s

Acceleration:            5.48rpm/s    27.92rpm/s    34.12rpm/s