Orbits
This lesson covers:
- Why objects orbit each other
- Why orbiting objects are constantly accelerating even though their speed doesn't change
- How the speed of an object's orbit is related to the size of their orbit path
An orbit is the curved path of one celestial object or spacecraft, around another celestial object.
Which of Newton's three laws is this:
"An object travelling at a certain velocity will continue to travel at that velocity unless acted upon by a resultant force."
First law
Third law
Second law
|
The diagram above shows the moon orbiting the earth.
Which arrow, A or B, shows the direction of the instantaneous velocity?
A
B
|
The diagram above shows the moon orbiting the earth.
Which arrow, A or B, shows the direction of the force of gravity?
A
B
|
Velocity is a vector quantity which means it has both magnitude and direction.
During orbit, one of these quantities is constantly changing, which means the velocity is also constantly changing.
Which quantity is constantly changing?
Magnitude
Direction
|
Which statement about objects in orbit is true?
The speed is changing and the velocity is constant
The speed and velocity are both constant
The speed is constant but the velocity is changing
The speed and velocity are both changing
|
Which of these correctly explains whether an orbiting object is accelerating, and why?
The object is accelerating because the velocity is changing
The object is accelerating because the speed is changing
The object is not accelerating because the velocity is constant
The object is not accelerating because the speed is constant
|
If an object moves closer to the object it's orbiting, it will experience a greater force of gravitational attraction.
What is required for the object to stay in orbit?
The magnitude of the velocity must stay the same
The magnitude of the velocity must increase
The magnitude of the velocity must decrease
|
What provides the force needed to keep a satellite in its orbit?
Friction
Tension
Gravity
|