Purpose: to investigate the quantitative aspects of the electric force between two objects, including the dependences on both distance and charge.Also, to place the electric force into context with our force problem-solving process from first-semester physics.Lab 1 – Coulomb’s Law Investigating the force between charged objects Purpose: to investigate the quantitative aspects of the electric force between two objects, including the dependences on both distance and charge. Also, to place the electric force into context with our force problem-solving process from first-semester physics. Introduction Coulomb’s Law: “The magnitude of the electric force that a particle exerts on another is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.” Mathematically, the magnitude of this electrostatic force FE acting on two charged particles (q1, q2) is expressed as: 𝑞 𝑞 FE = k 𝑟1 2 2 Where r is the separation distance between the charged objects and k is a constant of proportionality, called the Coulomb constant, k = 8.99 × 109 Nm2/C2. Part 1 – Determining the value of Coulomb’s constant k Experiment 1-A: How the force depends on distance 1- Click on the following link and select the “Macro Scale” version of simulation. Set your own values for Charge 1 (q1) and Charge 2 (q2), and write their values in the first row of Table 1 below. These values will remain the same for all trials in Table 1. https://phet.colorado.edu/sims/html/coulombs-law/latest/coulombs-law_en.html 2- Change the distance between the two charges to match each of the values given in Table 1. The ruler is marked in centimeters, and each charge can be placed to the nearest centimeter. 3- For each distance value, record the force value given by the simulation. 4- Fill in the rest of Table 1 by calculating the values of r2 and 1/r2 in the specified units. Table 1 q1 (𝜇C) q2 (𝜇C) -4 8 r (cm) 10 9 8 Use the same charge values above in all trials that follow. 7 6 5 4 3 2 r2 (m2) 1/r2 (1/m2) FE (N) 0.01 100 28.760 0.0081 123.457 35.506 0.0064 156.25 44.938 0.0049 204.08 58.694 0.0036 277.778 79.889 0.0025 400 115.041 0.0016 625 179.751 0.0009 1111.111 319.557 Analysis for Experiment 1-A: 5- Use Excel software and the data from Table 1 to make a graph of FE versus r. (With r on the horizontal axis.) What do you notice about the shape of the graph? Fe VS r 1200 1000 Fe (N) 800 600 400 200 0 10 9 8 7 -200 6 5 4 3 r (cm) As the distance decreases the force increases 6- Use Excel to make a graph of FE (in Newtons) versus 1/r2 (in 1/m2). Add a trendline to the graph and use its slope to find Coulomb’s constant k. Fe VS 1/r2 1200 1000 Fe (N) 800 600 400 200 0 10 -200 9 8 7 6 1/r2 (1/m2) 3 5 4 3 7- Calculate the percent error in k (where kknown = 8.99 × 109 Nm2/C2). Also, is the percent error value what you would expect in this case? Why or why not? Note: Include screenshots of all created graphs with your lab report. Experiment 1-B: How the force depends on charge 8- Reset the “Macro Scale” simulation, and set the value of charge q2 and the distance r, as shown in Table 2