Newton's Laws with an Atwood's Machine

Try this

The relationship between mass, net force, and acceleration of an object is frequently displayed using an Atwood’s Machine (two masses suspended over a pulley system) or a modified Atwood’s Machine (one mass suspended over a pulley system, pulling on a frictionless object over a horizontal surface).

Using the Accelerometer tool, place the mobile device in a plastic bag and suspend it from a traditional or modified Atwood’s Machine composed of pulleys and string. Using known masses and mass of the mobile device using a balance, determine the net force on each object. Use the data to determine the acceleration. Perform experiments in which acceleration is measured resulting from changes in mass and net force on the system.

Challenge yourself

• Create a graph of Net Force vs. Acceleration, and derive a mathematical expression for this relationship.
• Creat a graph of Mass vs. Acceleration, and derive a mathematical expression for this relationship.
• If there are any constants in the mathematical expressions above, explain their significance.
• Combine the two expressions into a single expression.
• Using the expression and a new system of given mass, estimate the expected acceleration. Compare to the actual acceleration observed using the smartphone data.