In this lab you will use at Atwood’s Machine to explore
Newton’s Second Law. Mr. Atwood designed this machine to
measure g.

Materials

pulley

about 1 - 2 m of string

stopwatch

several large paperclips

physics classroom masses

Procedure

The following conditions must be met in each set-up that you
use:

m_{2} – m_{1} ≤ 10 g

200 g ≤ Σm ≤ 250 g

(Σm means the sum of the two masses)

Set up an Atwood’s Machine using four different
combinations of masses. Make sure to abide by the restrictions
given above. For each setup calculate the theoretical
acceleration. Show the free body diagram (that is, the force
arrows) on each mass. Do this in your lab notebook as a first
draft for what you will hand in.

For each Atwood’s Machine setup measure the actual
acceleration. Design your own procedure to accomplish this.

Analysis

Create a neat data table to contain all of the information
you will need to perform the following analysis. Show results in
the same data table.

Compute theoretical accelerations for each setup you
used.

Compare the theoretical acceleration to the acceleration you
measured. Calculate a percent error for each setup.

Explain any discrepancy between the experimental acceleration and the theoretical acceleration. Do not draw on ‘human
error‘ to do this but instead discuss physical limitations
of the equipment/techniques used to make the measurement. Also, you may refer to assumptions made, such as that the pulley is frictionless or has no mass.

Above and beyond: Show algebraically how
this experiment could be used to make an estimate of g, the
acceleration due to Earth’s gravity. Use your method to
find g for each setup for which you measured the acceleration.
Explain any discrepancy between the value that you find and the
correct value of 9.8 m/s^{2}. Abide by the restrictions outlined above regarding how to address experimental error.

To Hand In

Hand in your data table, calculations (with diagrams), and the results of the analysis requested above. Do this by hand or on a computer but neatness counts. Show units and show all work for calculations and use a step-by-step approach.