Topic 8 - Space Physics

Question 1

How does the velocity of a planet in orbit change even though its speed is constant?

Answer 1

Speed is a Scalar Quantity, velocity is a vector quantity. This means it has magnitude and direction
In orbit, the direction is changing constantly, so the velocity will change while the speed will be kept the same.

Question 2

Order of orbits

Answer 2

In ascending order:

Satellites (natural or artificial)
Planets
Stars
Galaxy Centre
Galaxy Cluster Centre