Lab activity ellipses answer key

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NOTE: Question 13 (in the Kepler's 2nd law section) asks you to use the simulator to note the size of the sweep segment for an eccentricity of 0.5. To receive credit for the lab, in addition to your written answer, you must include a screenshot of the simulator with at least three sweep sections shown. Pease upload the screenshot with your final lab submission.Name: Planetary Orbit Simulator – Student Guide Background Material Answer the following questions after reviewing the “Kepler's Laws and Planetary Motion” and “Newton and Planetary Motion” background pages. Question 1: Draw a line connecting each law on the left with a description of it on the right. only a force acting on an object can change its motion Kepler’s 1st Law Kepler’s 2nd Law planets move faster when close to the sun Kepler’s 3rd Law Newton’s 1st Law planets orbit the sun in elliptical paths planets with large orbits take a long time to complete an orbit Question 2: When written as P2 = a3 Kepler's 3rd Law (with P in years and a in AU) is applicable to … a) any object orbiting our sun. b) any object orbiting any star. c) any object orbiting any other object. Question 3: The ellipse to the right has an eccentricity of about … a) 0.25 b) 0.5 c) 0.75 d) 0.9 Question 4: For a planet in an elliptical orbit to “sweep out equal areas in equal amounts of time” it must … a) move slowest when near the sun. b) move fastest when near the sun. c) move at the same speed at all times. d) have a perfectly circular orbit. NAAP – Planetary Orbit Simulator 1/8 Question 5: If a planet is twice as far from the sun at aphelion than at perihelion, then the strength of the gravitational force at aphelion will be as it is at perihelion. a) four times as much b) twice as much c) the same d) one half as much e) one quarter as much Kepler’s 1st Law If you have not already done so, launch the NAAP Planetary Orbit Simulator. • Open the Kepler’s 1st Law tab if it is not already (it’s open by default). • Enable all 5 check boxes. • The white dot is the “simulated planet”. One can click on it and drag it around. • Change the size of the orbit with the semimajor axis slider. Note how the background grid indicates change in scale while the displayed orbit size remains the same. • Change the eccentricity and note how it affects the shape of the orbit. Tip: You can change the value of a slider by clicking on the slider bar or by entering a number in the value box. Be aware that the ranges of several parameters are limited by practical issues that occur when creating a simulator rather than any true physical limitations. We have limited the semi-major axis to 50 AU since that covers most of the objects in which we are interested in our solar system and have limited eccentricity to 0.7 since the ellipses would be hard to fit on the screen for larger values. Note that the semi-major axis is aligned horizontally for all elliptical orbits created in this simulator, where they are randomly aligned in our solar system. • Animate the simulated planet. You may need to increase the animation rate for very large orbits or decrease it for small ones. • The planetary presets set the simulated planet’s parameters to those like our solar system’s planets. Explore these options. Question 6: For what eccentricity is the secondary focus (which is usually empty) located at the sun? What is the shape of this orbit? Question 7: Create an orbit with a = 20 AU and e = 0. Drag the planet first to the far left of the ellipse and then to the far right. What are the values of r1 and r2 at these locations?