Space

Question 1

For projectile motion, what is the only equation you should use for the vertical part of the motion?

Answer 1

For the vertical part of the motion, the only equation which should be used is

Question 2

What is the difference between mass and weight?

Answer 2

Mass is a measure of the amount of ‘stuff’ that makes up an object.

Weight is the force due to gravity acting on an object.

Question 3

By referring to the horizontal and vertical parts of its motion, explain the curved path of a projectile.

Answer 3

A projectile has

constant horizontal velocity and

constant vertical acceleration.

Question 4

What is meant by terminal velocity?

Answer 4

When a falling object (e.g. a skydiver) accelerates, the air resistance acting against the object increases, until it is balanced with the object’s weight. When the forces are balanced, it will travel at a constant speed (called ‘terminal velocity’).

Question 5

What does the prefix M stand for?

Answer 5

M stands for mega

mega = x 10⁶

Question 6

What is a star?

Answer 6

A star is a sphere of plasma that emits heat and light.

Question 7

What is the relationship between the altitude of a satellite (height above the Earth) and its period (time taken to complete one orbit of the Earth)?

Answer 7

The higher the altitude, the longer the period of the satellite.

Question 8

What are the different types of wave detected by space telescopes?

Answer 8

As well as visible light, space telescopes detect infrared (IR), ultraviolet (UV), X-rays and gamma rays.

Question 9

What is a moon?

Answer 9

A moon is a natural satellite of a planet.

Question 10

What does the prefix G stand for?

Answer 10

G stands for giga

giga = x 10⁹

Question 11

What is a dwarf planet?

Answer 11

A dwarf planet is an object which orbits the Sun but, due its small mass, whose orbit is not uniform enough to be classed as a planet.

Question 12

What is the unit for weight?

Answer 12

The unit for weight is

newtons (N)

Question 13

What is a galaxy?

Answer 13

A galaxy is a group of stars, gases and dust held together by gravity.

Question 14

Is the mass of an object constant at all points in the universe?

Answer 14

Yes. The mass of an object does not change, regardless of the force of gravity.

1kg on Earth would be 1kg on the Moon, 1kg in outer space, and so on.

Question 15

Describe how to calculate one light-year in metres.

Answer 15

Use the formula d = v x t :

• v = 3 x 10⁸ ms^-1 (speed of light)
• t = 1 year (convert into seconds: 365.25 x 24 x 60 x 60)
• Calculate d

Question 16

Explain the orbit of a satellite in terms of projectile motion.

Answer 16

A satellite is like a projectile: it is travelling ‘forwards’ (horizontally) with a constant velocity, but also accelerating ‘downwards’ (vertically).

Question 17

Is the weight of an object constant at all points in the universe?

Answer 17

No - the weight of an object depends on its mass and the gravitational field strength. Therefore, the weight of an object can vary at different points in the universe.

Question 18

What is the Sun?

Answer 18

The Sun is the star at the centre of our solar system.

Question 19

Use Newton’s 3rd Law to explain how a rocket accelerates.

Answer 19

Newton’s 3rd Law is about action and reaction forces.

In a rocket, the rocket pushes the combustion gases downwards, and the gases push back up against the rocket (causing it to accelerate).

Question 20

What does the prefix m stand for?

Answer 20

m stands for milli

milli = x 10^-3

Question 21

What is a solar system?

Answer 21

A solar system is a collection of objects orbiting a star.

Question 22

What is a projectile?

Answer 22

A projectile is an object which is moving only under the influence of gravity.

(assume that air resistance is negligible)

Question 23

What name is given to this pattern, produced when a source of white light is viewed through a spectroscope?

Answer 23

When white light is viewed through a spectroscope, a continuous spectrum is produced.

Question 24

Describe some of the risks of space exploration.

Answer 24

• Astronauts can be exposed to a high level of radiation, without the Earth’s atmosphere to absorb some of the cosmic rays
•  Space is a vacuum, and so there is a large difference in pressure between the inside of a spacecraft (or spacesuit) and outside
• Astronauts’ bodies can suffer loss of muscle mass and weakening of bones due to weightlessness whilst in orbit
•  Re-entry to a planet’s atmosphere creates a large amount of heat due to air resistance. Thermal protection systems must be used to ensure the spacecraft is protected on re-entry.
•  The angle of re-entry must be precisely calculated so the spacecraft doesn’t ‘bounce off’ the atmosphere.

Question 25

What is meant by the

‘observable universe’?

Answer 25

The furthest point in space that we can see is the distance light must have travelled for the whole age of the universe.

This distance is called the ‘observable universe’.

Question 26

Name the three quantities shown in this formula.

Answer 26

F = unbalanced force

m = mass

a = acceleration

Question 27

Describe some of the benefits of space exploration.

Answer 27

Space exploration has helped to develop

•  The accuracy of weather forecasting
•  Telecommunications via satellites
•  Analysis of our environment
•  National security
•  Sat-Nav systems
•  Robotics

Question 28

Why are distances in space measured in light-years?

Answer 28

Distances in space are vast. They are too big to be easily understood using metres. A light-year is large enough to be suitable for describing the distance between objects in space.

Question 29

What name is given to this pattern, produced when certain elements are viewed through a spectroscope?

Answer 29

When elements (in a star, or produced by a discharge lamp) are viewed through a spectroscope, a line spectrum is produced.

Question 30

For projectile motion, what is the only equation you should use for the horizontal part of the motion?

Answer 30

For the horizontal part of the motion, the only equation which should be used is

Question 31

What is a planet?

Answer 31

A planet is an object in orbit around a star.

Question 32

What is an exo-planet?

Answer 32

An exo-planet is a planet outwith our solar system.

Question 33

What is Newton’s 2nd Law?

Answer 33

If the forces on an object are unbalanced, the object will accelerate in the direction of the unbalanced force.

F = m x a

Question 34

What impact has space exploration had on our understanding of the universe?

Answer 34

• Hubble’s deep field lens allows us to capture images across many wavelengths of EM radiation from deep space.
• Voyager has performed ‘fly-pasts’ of many objects in our solar system giving up-close, detailed images never seen before.
• Spirit analysed the terrain on Mars to help determine if life had ever existed there.

Question 35

What does the prefix µ stand for?

Answer 35

µ stands for micro

micro = x 10^-6

Question 36

What is meant by balanced forces?

Answer 36

Balanced forces means forces which are the same size but in opposite directions.

Question 37

What is Newton’s 3rd Law?

Answer 37

Newton’s 3rd Law states that for every ‘action’ force there is an equal but opposite ‘reaction’ force.

Question 38

What is an asteroid?

Answer 38

An asteroid is a small rocky body orbiting the Sun.

Question 39

What does the prefix k stand for?

Answer 39

k stands for kilo

kilo = x 10³

Question 40

What is required for a planet to be able to sustain life?

Answer 40

To sustain life, a planet must be within the right temperature range - it must be capable of having liquid water and an oxygen-rich atmosphere.

Question 41

What is the universe?

Answer 41

The universe is all existing matter and space.

Question 42

What does the prefix n stand for?

Answer 42

n stands for nano

nano = x 10^-9

Question 43

In space physics, how do scientists use line spectra?

Answer 43

Scientists use line spectra to identify the different elements present in stars and galaxies.