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

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

• Also comes with a meter stick and a stop watch.

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

• The demonstration has two small cans filled with wax.

• Each can with wax has a mass of ( )grams = M

• Added to or removed from each can are couple of pennies.

• Each penny has a mass of (~3.2 grams )grams = m.

• Demo begins with each can containing the same number of pennies.

• As a penny is moved from can (A) to can (B).

• Side (A) is now pennyless, its mass is (M).

• Side (B) now has 2 pennies, so its mass is (M + 2m).

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

• This demo can be done with four pennies of equal mass as well.

• Start with (M + 2m) on each side.

• After the transfer, side (A) has a mass of (M) and

the mass of side (B) becomes (M + 4m).

.

Last Updated 2/98 - University of Texas at Austin Physics Dept. - All Rights Reserved.