Physical Science I PHYS 14-15 Lab 4 Projectile Motion Purpose To investigate projectile motion with a rocket using a computer simulation experimenting with various launch angles to determine a maximum launch angle and how air resistance would affect this maximum launch angle. Discussion Projectile motion under ideal conditions can be best described as a parabola, as determined by Galileo. Ideal conditions infer the existence, or rather, the absence of air resistance. This lab will include experimenting with launching a cannonball with varying launch angles to determine a maximum launch angle. This launch angle will then factor in air resistance and a new maximum launch angle will be determined. Recall projectile motion consists of horizontal and vertical velocities. Vertical velocities are greater than horizontal velocities for angles greater than 45 degrees. Horizontal velocities are greater than vertical velocities for angles less than 45 degrees. Procedure SETUP Open the simulation: htt s: het.colorado.edu sims html ro'ectile-motion latest ro'ectile-motion en.html PART A: Determining Launch Angles Once the simulation opens, select the last option, Lab and open it. Note: depending on the version of program being used, object lists and features may differ slightly. Try to familiarize yourself with the simulation by experimenting with the different menu options. Step 1: Determining the maximum launch angle a. Click and drag the measuring tape down and place it by the cannon. The crosshairs of the two should be aligned, and the tape can be extended to the right all the way until the edge of the screen. The measuring tape will be used to measure the horizontal launch distance. b. Change the "Diameter" of the Cannonball to "0.8 m," and the "Mass" to "5 kg.\" c. The default setting for the cannon angle is 80 degrees. Press the launch button (red button in the object list). Measure the horizontal distance and record the value. (1. Click and drag the launcher to change the angle, you may choose to do this by decreasing the angle by 10 degrees or a similar value. Vary the angle to discover the maximum launch angle, this would be the angle that results in the maximum horizontal distance. Use the table below to record your values. (Fill the ENTIRE table with data points) Physical Science I PHYS 14-15 (degrees) Horizontal distance (m) Launch Angle 80 e. Record the maximum launch angle [the angle that yields the greatest horizontal distance] and it's coordinating horizontal distance below. Step 2: Factoring in air resistance a. Predict. Reset your simulation to default settings by clicking the refresh button on the bottom of your screen. Check the box enabling Air Resistance in the object list. Enter the altitude in meters at your location [If you are not sure ofyour altitude, you can conduct a quick search online with your location and the word, 'altitude.') Predict what would happen, if anything, to the horizontal distances listed in the table above for each respective angle. Do not play the simulation. b. Observe. Play the simulation and repeat Step 1, part c. Use the table below to record your values. [Fill the ENTIRE table with data points) (degrees) Horizontal distance (m) Launch Angle 80 Physical Science I PHYS 14-15 Launch Angle Horizontal (degrees) distance (m) c. Record the maximum launch angle [the angle that yields the greatest horizontal distance) and it's coordinating horizontal distance below. 8. Explain. How does the maximum launch angle above compare to the angle in Step 1, part d? Why does air resistance make a difference? [Make sure your response includes the horizontal/vertical velocities and what happens to them)