Satellites: orbital speed and period

Answer Key - Grade 11 Science Worksheet - Building Confidence

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

1. 1.

   NASA says the ISS goes around Earth about 16 times a day. How many minutes does one orbit take, Ari?

   90 min
2. 2.

   A model satellite goes around Earth 15 times a day. How many minutes does one orbit take, Bo?

   96 min
3. 3.

   A model satellite in a low test orbit goes around Earth 18 times a day. How many minutes does one orbit take, Esme?

   80 min

4. Read this first

   Orbit diagram (NASA values)

   The ISS circles Earth 370–460 km above the surface. A velocity arrow points along the orbit; a gravity arrow points from the ISS to Earth's center.

5. 4.

   In the diagram, which way does gravity pull the ISS, Jun?

   • Toward Earth's center
   • Away from Earth
   • Along its orbit
6. 5.

   In the diagram, what would the ISS do if gravity suddenly stopped, Kira?

   • Keep circling Earth in the same orbit
   • Fall straight down
   • Go straight along its velocity
7. 6.

   In the diagram, why doesn't the ISS fall to the ground, Luz?

   • Gravity doesn't reach it
   • Its sideways speed carries it around as it falls
   • It sits on top of the air
8. 7.

   The ISS orbits 370–460 km up; the Moon orbits 384,400 km away. Which moves faster in its orbit, Milo?

   • They move at the same speed
   • The Moon, since its orbit is bigger
   • The ISS
9. 8.

   NASA gives the Moon's orbital speed as 1.022 km/s. The ISS moves at about 7.7 km/s. About how many times as fast is the ISS, Noah?

   • About the same speed
   • About 7.5 times
   • About 75 times
10. 9.

    What keeps the ISS circling Earth instead of flying off into space, Ren?

    • Its engines pushing it up
    • It is above the reach of gravity
    • Earth's gravity
11. 10.

    A tool let go of inside the ISS floats beside the wall. Why, Tala?

    • Both fall around Earth together
    • There is no gravity at the ISS's height
    • Air inside holds it up