PIRA 1G10.40 Force, Mass, and Acceleration: Atwood's Machine

Instructions / Notes:

• A low-friction light pulley and a combination masses (2M + 1m or 2m).

• The apparatus comes with a meter stick and a stop watch.

• Faculty may want to preview the actual demo before ordering.

• The demonstration has two LARGE Masses of (M>)- 200 grams each.

• Two or four little masses - 5 grams each - which can be transferred.
• Each little mass is symbolized as (m) in the examples below.

• Example: 1(M) versus 1(M) plus 2(m) on opposing side.
• Total mass of both sides together = 410 grams

• Example 2 below is for someone who wants to use class time to make 2 measurements.
• To do 2 measurements, four little masses of 5 grams each are needed.

• Example 2: 1(M) plus 1(m) on one side versus 1(M) plus 3 (m) on the opposing side.
• Total mass of both sides together = 420 grams

• Example 2, part B: 1(M) on one side, then 1M plus four 5 gram weights on the other.
• Total mass of both sides together on this second run = 420 grams

• Once again, LARGE (M) = 200 grams and each little (m) = 5 grams

• The image shows each 200 gram mass containing the same number of 5 gram masses.

• The demo number in the image should be labelled 1G10.40 not 5G10.40.

• A stopwatch is used to measure the time it takes (B) to fall 1 meter.

• Demo Staff: Start with (M + 2m) on each side.

Last Updated 3/10 - University of Texas at Austin Physics Dept. - All Rights Reserved.