Course Content
Formula Sheet
Example 1
A student makes the following statements about the Universe.
The best way to go about multiple choice questions is to rule options out.
The first statement is correct.
The Big Bang theory is an effort to explain what happened at the start of the Universe.
The second statement is not correct.
The Universe is approximately 14 billion years old.
The third statement is correct.
The Universe is expanding.
So the answer is D
Example 2
A satellite is in a circular orbit around a planet.
To excel in the Space section of the exam, you should refer to the course specification and ensure you know all the definitions.
The first statement is not correct.
The greater the altitude of a satellite, the greater its orbital period.
The second statement is correct.
The satellite is a projectile, and with any projectile, the vertical acceleration is constant.
The third statement is not correct.
In orbit, the satellite is constantly falling toward the planet due to gravity, but its sideways motion keeps it moving around the planet, keeping it at the same height due to the curvature of the planet.
This means its vertical velocity stays balanced and doesn't increase.
So the answer is B
Example 3
The star Wolf 359 is at a distance of 7.8 light-years from Earth.
Calculate the distance, in metres, from Wolf 359 to Earth.
1 light-year is the distance light travels in one year.
We can work this out by calculating how many seconds are in a year and multiplying this by the speed of light.
To calculate the distance of 7.8 light-years, we simple calculate how many seconds are in 7.8 years.
We use:
d = vt
d = 3 x 108 x (60 x 60 x 24 x 365.25 x 7.8)
Just a reminder that its 60 seconds times 60 minutes etc.
Also, when doing these calculations we tend to use 365.25 days,
as this is the true number of days in a year!
So d = 7.4 x 1016 m
Example 4
Define the term galaxy.
With the space topic, its best you learn the definitons of all the space terms
e.g. stars, planets, moons etc.
A galaxy is a collection of gas, dust and billions of stars.
Example 5
Far out in space, the rocket engine of a space probe is switched on for a short time causing it to accelerate.
When the engine is then switched off, the probe will
We should be thinking of the forces acting on the space probe.
When the engine is switched off, there will be no longer be a thrust force acting on the space probe.
And since we are in space, there is no air resistance acting on the space probe.
Therefore, there is balanced forces.
So the answer is D