Ontario Grade 9 Science Class Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

Master Grade 9 Science with our comprehensive practice exam. Test your knowledge, identify weak areas, and boost your confidence for academic success.

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

What is retrograde motion?

A large cloud of dust and gas.
The movement of planets in a backward (westward) direction relative to the stars.
A small body moving in the solar system.
The mass of an atom.

The correct answer is: The movement of planets in a backward (westward) direction relative to the stars.

Retrograde motion refers specifically to the apparent backward (westward) movement of planets in the sky, as observed from Earth's perspective. It is a result of the differing orbital speeds and paths of Earth and the planets, and does not refer to a specific type of body or object like a cloud of dust and gas (A), small body (C), or the mass of an atom (D). Therefore, these options are incorrect in relation to the question about retrograde motion.