LAB 3

First of all, please see this projectile motion simulation. The entire lab will be using this simulation so please let me know if you have any trouble accessing it. Reminder: All graphs and excel/spreadsheets should be included in your submissions. Projectile Motion Projectile motion is a very specific type of motion, where the acceleration in the horizontal direction (often called the "x" direction) is zero, and the acceleration in the vertical direction (often the "y" direction) is downwards at 9.81 m/s'. This is the motion that describes an object that is thrown or dropped, including objects launched at high speeds. The only caveats in our case is that we are ignoring air resistance, and we are staying close to the surface of Earth. Part 1 1. Open up the PhET simulation and play around with it, just to get comfortable. 2. On the very bottom, select "Intro." Also, click the yellow reset button in the bottom right just in case. 3. Set the height of the cannon to Om, it should appear to be set downward into the ground. 4. Select an initial velocity and angle. Pick any angle other than 90 degrees. o Pick any initial velocity other than 0 m/s. Question 1: What initial angle and velocity did you pick? What is the precision of these values? 5. Launch the projectile and find the range (maximum horizontal distance). o Use the tape measure to measure the range. Question 2: What was the range of the cannon? What is the uncertainty? 6. Compute the range (the final horizontal position) of the projectile using your kinematic equations. o Question 3: Showing all work, what is the expected projectile range? What is the uncertainty? 7. Compare and verify that the simulation agrees with the kinematic equations. There are lots of ways to compare quantities. I recommend using percent difference as it compares relative size. Percent difference = [Theoretical-Experimental//Theoretical x100%In the physical world there is an obvious distinction between what is "experimental" and "theoretical," but this distinction gets blurred in the all-online simulation based lab course. As clarification, I expect the "experimental" numbers to come from the simulation, and the "theoretical" numbers to come from your calculations Question 4: How does that calculated range compare to the range from the simulation? Part 2 Last week we used this simulation to graph the x and y positions as functions of time (meaning that x and y positions were on the vertical axis, and time was on the horizontal axis). This week we are going to plot x and y velocities versus time. 1. Continue using the same cannon setup as Part 1. 2. Use the blue data crosshair tool to grab all of the data for the first 10 points of projectile motion. Use a spreadsheet software (or make a table by hand) to record x position, y position, and time for these first 10 points. We are limiting to 10 points so that people who picked a bigger trajectory in part 1 o Question 5: This table should be submitted/labelled for this "question" 3. Use that data table to compute the average x and y velocities from point to point. Use the average velocity equation: V,=Ax/At to compute a velocity for each time (minus one) You will end up with 9 average velocities in the horizontal and 9 average velocities in the vertical for the 10 data points taken. This is because each velocity requires two positions and times. You can (and should) use your spreadsheet software to do these computations for you. Question 6: The table including these velocities should be submitted/labelled for this "question". 4. Plot x velocity vs time in a graph, with a linear trend line. You will need to pick 9 times to correspond to the 9 velocities. I recommend picking half intervals. ie: If your times are 0.0s, 0.1s, 0.2s, ... then pick times of 0.05s, 0.15s, 0.25s etc. You can also pick to just plot it at either the beginning or end of the time intervals (basically just dropping either the first or last time datum).0. Question 7: What is the slope of the trendline? What does tha you about the x velocity as a function at time? 5. Plot y velocity us time in a graph, wit a linear trend line. c You will need to pick 9 times to correspond to the 9 velocities again. just use the same process as before. c Question 3: What is the slope of the trendline? What does the you about me y velocity as a function or time