Circular Orbits Flashcards

All 6 cards in this deck

What force keeps a planet or satellite in a circular orbit, and in which direction does it act?

Gravity, acting towards the centre of the orbit (a centripetal force).

For an object in a circular orbit, what stays constant and what changes?

The speed stays constant but the velocity changes, because the direction of motion keeps changing.

True or false? A satellite moving in a circular orbit at constant speed is accelerating.

True. Its direction, and so its velocity, is always changing.

What is a geostationary satellite's orbit like?

A circular orbit above the equator with a period of 24 hours, so it stays above the same point on the Earth's surface.

What is a near-Earth (low) orbit satellite used for?

Monitoring the weather and imaging the Earth's surface; it orbits in a few hours and passes over different parts of the Earth.

How does the orbital period of a planet change with its distance from the Sun?

The greater the orbital radius, the longer the orbital period (and the slower the orbital speed).

e.g. Jupiter takes far longer than Earth to orbit once.