Name_________________________________________ Class period: _________ Date: ________________ PhET Projectile Motion Lab – part 1 Google “PhET Projectile”, it will be the first hit Then click the button beneath the picture. Take a few minutes to familiarize yourself with the simulation and shoot stuff with the cannon. Once you’ve somewhat satisfied your primal desires to shoot things, follow along with the questions below. Use complete sentences. Click on the “Lab” icon on the bottom. Play with the tools that are on the top to find out what they do. Shoot the cannon a few times and use the tools to find the range, maximum height, etc. Notice that the maximum height on the trajectory path is marked by a green circle. 1. Make a prediction for the following scenarios. Do not consider air resistance. Once you have made your prediction, only then, try it out and see if your prediction matches reality: a. Do you EXPECT the horizontal distance (Range) an object flies to depend on the mass? (try different objects) EXPECTATION: _____________________ REALITY: _____________________________ b. Do you EXPECT a Car to fly longer or shorter distance than a golf ball given the same initial speeds and launch angles? EXPECTATION: ___________________ REALITY: ___________________________ c. Do you EXPECT the vertical distance (Maximum height) to be dependent on its mass? EXPECTATION: ___________________ REALITY: ___________________________ d. Do you EXPECT a Car to climb up higher or lower than a golf ball given the same initial speeds and launch angles? EXPECTATION: ___________________ REALITY: ___________________________ 2. Pick any initial speed and launch angle, and try out firing all the different objects (Golfball -> Car). a. How does the mass of an object affect its motion through the air? b. If you include air resistance, how does the mass of the object affect its motion through the air? Try it with the same object (same surface area), but different masses and give me the relationship. 3. Fire the projectile launcher straight upwards (angle = 90o) at 18 m/s. Using kinematics equations, determine: a) the time it should take the projectile to reach maximum height (show all work below and verify it with the sim.) b) the maximum height reached by the projectile (show all work and verify with the sim) 4. You are now going to investigate the effect of launch angle on several different parameters; air time, maximum height, and range. (continues on next page) Fire the projectile launcher at the following angles (with the same initial speed of 18 m/s), then fill in the table below. You will need to use the measuring tape to measure the maximum height and the range. Angle Initial Speed (m/s) 25o 30o 35o 40o 45o 50o 55o 60o 65o 70o 80o 90o 18 18 18 18 18 18 18 18 18 18 18 18 Air Time (s) Maximum Height (m) Range (m) a. What is the best angle for maximum height and air time? Explain why you think this is so. b. Is there a direct relationship between air time and range? Explain why or why not. This is an important question, make sure to give it some serious thought. c. Which of your angles above gave the most range? Explain why you think this is so. d. Compare the ranges in your table above. Can you see a pattern? State it below: If the initial speed is constant, two launch angles that add to _____ o will give the same range. e. Why do you think this is so? f. Does varying the initial speed affect your results to parts (c) and (d)? Perform a quick experiment to test this out. Why do you think this is the case? g. What effect does doubling the initial speed have on the range of the projectile? Explain your results.