AP Physics 1‎ > ‎Unit 2‎ > ‎

### Satellite Lab

 Satellite Playground LabPurpose:In this activity you will be examining the factors that affect the speed of a satellite around a planet.  You will also rediscovering one of the historically important laws of orbital motion.  Finally you will be looking at what it means for an orbit to be geostationary.Procedure:Part 1:  Satellite Mass and SpeedOpen the satellite playground program found here.Pick one of the actual solar system objects as your central body.  Keep this constant throughout this entire part of the lab.Raise or lower the distance from the center of the planet to the satellite.  Once you are happy with your location, keep this constant for this entire portion of the lab. Record this radius and calculate the circumference of the orbit your satellite will be making.Create a data table that lists the names of each of the different satellite options for this program as well as their mass, the period of revolution and the speed of the satellite.Create graphs for period vs. mass and speed vs. mass and talk about the affect that a satellite's mass has on its orbital speed and period.Part 2:  Orbital Radius and SpeedPick one of the satellites from the program and use it for the entire rest of the experiment.  Keep the central body the same for the rest of this part of the experiment.Pull up the ruler and note how far the satellite is from the center of the Earth.  This distance is your orbital radius.  Depending on the scale for your planet, the ruler will be in kilometers or Megameters.  In the picture below the satellite is about 9.6 million meters from the center of the Earth.Create a data table that has room for you to track 8 different orbital radii and their associated orbital periods and speeds.At this time you will only be creating a graph of orbital speed vs orbital radius.  Make sure you get your equation for this graph and include with the picture of your graph in your lab book.Part 3:  Central Body Radius and SpeedFor this part of the lab you are going to have to switch over to your custom planet.  You will need to set up a mass for your planet and an orbital radius for your satellite.  Once these are set, don't vary them for the remainder of this part of the lab.Create a data table that gives the radius of the central body, the orbital period and the orbital speed of your satellite.  Collect data for 5 different planet radii.  Make sure each new radius is smaller than the one that proceeded it.  If you increase the radius of the planet, it might interfere with the orbit of the satellite.Create a graph and talk about the affect that central body's radius has on the satellite's orbital period and speed.Part 4:  Central Body Mass and SpeedFor this part of the lab you are going to be working with your custom planet.  You will need to set up a radius for your planet and an orbital radius for your satellite.  Once these are set, don't vary them for the remainder of this part of the lab.Create a data table that gives the mass of the central body, the orbital period and the orbital speed of your satellite.  Collect data for 5 different planet masses.Create a graph showing the speed of the satellite vs. planet mass.  Find the equation for this relationship and include it with your graph.Part 5:  Geostationary SatelliteSwitch your satellite to Sputnik and your central body to Vesta.Try to find the orbital radius that will cause the satellite to always stay over the exact same spot of Vesta's surface.Give your best guess as to this distance in your notebook.Part 6:  Kepler's Third Law of Satellite MotionIn 1619 Johannes Kepler published his third law of planetary motion.  We know know this same law applies to all orbiting satellites.Start by plotting a graph of period vs. orbital radius using the data you got from part 2 of this lab.  You will find that none of our simple relationships fit this data.Kepler found he could linearize this data by plotting a graph of orbital period squared vs. orbital radius cubed.  Try graphing your data again, but this time do what Kepler did and plot orbital period squared vs. radius cubed.Include both your graph and the resulting equation in your lab book.
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