For each part of your experiment, list each variable and indicate whether it was held constant, increased, or decreased. 2. Draw free-body diagrams for your experimental setup. Use Newton's laws to derive an expression for the acceleration of your Atwood machine. 3. How did changing the difference in masses affect the acceleration of the Atwood machine? 4. How did changing the sum of the mass affect the acceleration of the Atwood machine? 5. Use your data to derive two proportionality relationships between the acceleration and the total mass and the acceleration and the difference in mass. 6. Combine the two relationships to find a single relationship between acceleration, total mass and mass difference. Find the proportionality constant. 7. Compare your value for the proportionality constant with the value found using Newton's second law