Kepler's three laws of planetary motion
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
The orbit diagram marks point A (the ellipse's center), B (a focus) and C (a point on the curve). Where is the Sun, by Bo's reading?
- A, the center
- Outside the ellipse
- C, on the orbit
- B, a focus
Read this first
Orbits (NASA Planetary Fact Sheet)
Planet a (AU) T (years) e Mercury 0.387 0.241 0.206 Earth 1.000 1.000 0.017 Mars 1.524 1.881 0.094 Jupiter 5.20 11.86 0.049 Which planet in the table has the most stretched orbit, by Kira's reading?
- Mars, e = 0.094
- Earth, e = 0.017
- Mercury, e = 0.206
- Jupiter, e = 0.049
two shaded slices of equal area. What does Kepler's second law say a line from the Sun to a planet does, by Jun's reading (NASA)?
- Sweeps equal angles in equal times
- Sweeps larger areas when far away
- Sweeps equal areas in equal times
- Sweeps equal distances in equal times
Orbit diagram with perihelion and aphelion marked. Where in its orbit does a planet move fastest, by Luz's reading?
- Halfway between the two
- Closest to the Sun, at perihelion
- Farthest from the Sun, at aphelion
- At the same speed everywhere
Orbits (NASA Planetary Fact Sheet)
Planet a (AU) T (years) e Mercury 0.387 0.241 0.206 Earth 1.000 1.000 0.017 Mars 1.524 1.881 0.094 Jupiter 5.20 11.86 0.049 Which planet in the table takes longest to orbit the Sun, by Noah's reading?
- They each take one year
- Mercury, the closest
- Jupiter, the farthest out
- Mercury, since it moves fastest
Mars orbits at 1.524 AU. What is its orbital period in the table, by Pia's reading?
- 0.53 years, shorter than Earth's
- 1.881 years
- 3.54 years, its distance cubed
- 1.524 years, the same as its distance
Four equation cards, labeled A to D. Which equation is Kepler's third law, with T in years and a in AU, by Ren's reading?
- T² = a³
- T³ = a²
- T × a = 1
- T = a
Mercury (NASA)
Point Distance (million km) perihelion 46.0 aphelion 69.8 NASA lists Mercury's perihelion as 46.0 and its aphelion as 69.8 million km. By how much does its distance from the Sun change, by Tala's math?
- 23.8 million km
- 0 km, since its orbit is a circle
- 115.8 million km
- 57.9 million km
Earth (NASA)
Point Distance (million km) perihelion 147.1 aphelion 152.1 Earth is closest to the Sun in early January (NOAA). Why is January not summer in the Northern Hemisphere, by Zee's reading?
- The 5 million km change sets the seasons
- Seasons come from Earth's tilt, not its distance
- Earth's orbit is a perfect circle
- January is summer everywhere on Earth
Earth's orbital eccentricity is 0.017 (NASA). What does that tell Esme about the shape of the orbit?
- It is stretched enough to cause the seasons
- It is a perfect circle
- It is very stretched, like a comet's
- It is very nearly a circle
