Orbital speeds of planets and satellites

2 marks · Easy

Explain why satellites in low orbits travel at a higher speed than satellites in high orbits around Earth.

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show mark scheme and worked solution

Marking points

B1 · 1 mark · States that gravitational field strength is stronger closer to Earth (lower orbits).

B2 · 1 mark · Explains that a higher speed is needed in stronger gravitational field to stay in orbit.

Worked solution

Satellites in low orbits are closer to Earth where gravitational field strength is stronger. They must travel faster to stay in orbit and avoid being pulled down by gravity.