Satellites: orbital speed and period

Answer Key - Grade 11 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Earth's GM is 398,600 km³/s² and its radius is 6371 km. For a model satellite 400 km up, inside the ISS's range, what is the period in minutes, to the nearest tenth, Ari?

   92.4 min
2. 2.

   Earth's GM is 398,600 km³/s² and its radius is 6371 km. For a model satellite 1000 km up, what is the period in minutes, to the nearest tenth, Bo?

   105 min
3. 3.

   Earth's GM is 398,600 km³/s² and its radius is 6371 km. For a model satellite in a high test orbit 2000 km up, what is the period in minutes, to the nearest tenth, Esme?

   127 min

4. Read this first

   Circular orbits around Earth, worked out from Earth's GM (computed from NASA's GM)

   Height (km)	Speed (km/s)	Period (min)
   600	7.56	96.5
   1500	7.12	115.8
   10000	4.93	347.4
   35786	3.07	1435.7

5. 4.

   Using the table, how do speed and period change as the height goes up, Jun?

   • Speed falls and the period grows
   • Both stay about the same
   • Speed rises and the period grows
6. 5.

   Using the table, at which height does one orbit take about one day, Kira?

   • 10,000 km
   • 35,786 km
   • 600 km
7. 6.

   Milo says a satellite must go faster to stay in a higher circular orbit. Agree or disagree?

   • Agree: it has to fight more gravity up there
   • Disagree: higher circular orbits are slower
   • Agree: a bigger circle needs more speed
8. 7.

   Noah says the Moon moves faster than the ISS because its orbit is much bigger. Agree or disagree?

   • Disagree: the ISS is about 7.5 times as fast
   • Agree: the Moon is heavier
   • Agree: bigger orbits need higher speeds
9. 8.

   Pia says there is no gravity at the ISS's height. Agree or disagree?

   • Agree: gravity stops above the air
   • Agree: things float there, so gravity there is zero
   • Disagree: g there is still about 8.5–8.8 N/kg
10. 9.

    Why does draw a line from thin air make the ISS's orbit shrink over time, Tala?

    • Drag takes away energy, so it sinks lower
    • Drag pushes it outward
    • Drag adds energy
11. 10.

    The ISS takes about 92 minutes per orbit at 370 km and 94 at 460 km. Why is its period given as a range, Zee?

    • Its height changes, so its period changes too
    • Clocks on the ISS run unevenly
    • The ISS keeps changing its mass