Lab #1 - Stress- Strain Learning Objective: To determine the spring constant of a spring using Hooke's Law. Procedure: Go to website http://phet.colorado.edu/en/simulation/mass-spring-lab and run the "Lab" simulation. Follow the steps below to complete the lab: 1. Leave the Spring Constant 1 to default value. 2. Select Displacement and Movable Line option on the right side box. 3. Leave Earth as on option for Gravity. 4. Record the original length of spring using ruler from the second box on the right side. Record the value as Lo.. 5. Hang golden cylinder from the spring and change the mass to 50 g in the box at the top. 6. Use the ruler to measure the change in length of the spring and record it in column labeled L-Lo in the table below. 5. Change the masses, record the readings and calculate Stress and Strain for each mass. 6. Hang the Blue cylinder, record the change in length and calculate Strain Observations: (40 pts) Use Area A = 0.0001 m 9 = 9.8 m/s Original length Lo= Mass Mass m F= mg (g) (kg) (N) Stress=F/A (N/m) L-Lo Strain (L-Lo)/Lo 60 120 200 300 Blue mass Results: Plot a graph of Stress (Y axis) versus Strain (X axis) on the graph paper. Label all the points and axes. (20 pts) Analysis: Answer the following questions without using the Young's modulus or Spring Constant. Show all calculations for full credit. 1. From the graph, determine the change in length of spring when you hang 350 gm mass? (10 pts) 2. Find the value of the Blue unknown mass using the graph and calculated Strain value from the table. (10 pts) 3. Why are the displacement readings lower when the measurements are taken on Moon? Explain. (10 pts) 4. How will displacement readings of spring be affected when you increase the hardness (spring constant) of the spring? Why? (10 pts)