Orbital Speed

Aim: To investigate whether bodies in larger orbits move faster or slower.

Orbital Radius

Stopwatch

0.0sim-days

Data Table

# Radius, r (million km) Period, T (sim-days) Your speed, v (km/s) Check
  1. Start with the Earth preset (150 million km).
  2. Click Start Timer the instant the planet crosses the dashed marker line at the top of its orbit.
  3. Click Stop Timer the next time it crosses that same line, after one complete orbit. This is your period, T.
  4. Click Record Reading to log r and T in the table, then calculate the orbital speed v = 2πr ÷ T yourself (convert million km to km, and sim-days to seconds) and type it into the table to check your answer.
  5. Repeat for at least four different radii spanning the full range of the slider.
  6. Look at your table: as the orbital radius increases, does the orbital speed increase or decrease?