National 5 Projectiles & Space Flashcards

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1
Q

What is a projectile?

A

A projectile is an object which has two components of motion:

  1. a horizontal uniform velocity, and
  2. a vertical uniform acceleration downwards under gravity.

This causes the projectile to follow a parabolic trajectory (path).

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2
Q

Explain the curved path of a projectile.

A

A projectile has constant horizontal velocity and constant vertical acceleration due to gravity.

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3
Q

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

A

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

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4
Q

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

A

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

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5
Q

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

A

A satellite is a projectile: it is travelling horizontally with a constant velocity, but also accelerating vertically downwards so that the curve of its path (trajectory) matches the curve of the planet it is orbiting.

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6
Q

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)?

A

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

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7
Q

Describe some of the benefits of satellites.

A

Satellites have helped to develop:

  • The accuracy of weather forecasting
  • Worldwide continuous telecommunication
  • Analysis of our environment
  • National security
  • Sat-Nav/GPS systems
  • Our understanding of the universe through space telescopes
  • Our understanding of science through experiments performed in space (e.g. on the ISS)
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8
Q

What is meant by a geostationary orbit?

A

A geostationary orbit is an orbit in which a satellite would appear stationary when viewed from the Earth.

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9
Q

What are the properties of a geostationary orbit?

A
  • The orbital period is 24 hours.
  • The altitude is 36 000 km
  • The orbit is above the equator
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10
Q

What are the advantages of a geostationary orbit?

A

Since satellites in geostationary orbit do not appear to move from Earth, satellite dishes can be stationary and don’t need to ‘track’ the position of the satellite.

It also means that the satellite will never go out of view and continuous communication is available.

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11
Q

Describe some of the challenges associated with space exploration and possible solutions to these.

A
  • Travelling the large distances in space: This could be addressed using ion propulsion to produce a small unbalanced force over a large period of time.
  • Travelling the large distances in space: Another solution that has already been used is a ‘slingshot’ effect by passing close to a fast moving asteroid, moon or planet.
  • Manoeuvring a spacecraft in a zero friction environment is very difficult. Computers can be used to aid this.
  • Maintaining sufficient energy to operate life support systems in a spacecraft for long periods of time. A possible solution is using solar cells or nuclear reactors.
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12
Q

Describe some of the risks of space exploration.

A
  • The fuel load on take-off can lead to fire and explosions
  • 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
  • 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 or enter too fast.
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13
Q

Define what a light year is.

A

A light year is the distance travelled by light in one year.

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14
Q

Why are distances in space measured in light-years?

A

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.

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15
Q

Describe how to calculate one light-year in metres.

A

Use the formula d = v x t :

  • v = 3 x 108 ms-1 (speed of light)
  • t = 1 year (convert into s: 365.25 x 24 x 60 x 60)
  • Calculate d
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16
Q

Describe what is meant by the Big Bang.

A

The Big Bang marks the start of the universe, when everything was in an unimaginably small volume (almost a point) and rapidly expanded.

17
Q

State the approximate age of the universe.

A

Our current estimate of the age of the universe is 13.8 billion years.

18
Q

What is meant by the ‘observable universe’?

A

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

Everything within this distance is called the ‘observable universe’.

19
Q

What is a planet?

A

A planet is a large object in orbit around a star. (large enough to have cleared its own path of debris)

20
Q

What is a dwarf planet?

A

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

21
Q

What is a moon?

A

A moon is a natural satellite of a planet.

22
Q

What is the Sun?

A

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

23
Q

What is an asteroid?

A

An asteroid is a small rocky body orbiting the Sun.

24
Q

What is a solar system?

A

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

25
Q

What is a star?

A

A star is a sphere of gas (plasma) undergoing nuclear fusion and emitting heat and light.

26
Q

What is an exo-planet?

A

An exo-planet is a planet outwith our solar system i.e orbiting a star other than the Sun.

27
Q

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

A

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

28
Q

What is a galaxy?

A

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

29
Q

What is the universe?

A

The universe is all existing matter and space.

30
Q

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

A

As well as visible light, telescopes detect radio waves, infrared (IR), ultraviolet (UV), X-rays and Gamma rays to obtain information about astronomical objects.

31
Q

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

A

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

32
Q

What name is given to this pattern, produced when hot elements in gas form are viewed through a spectroscope?

A

A line spectrum.

33
Q

In space physics, how do scientists use line spectra?

A

Each element has a unique line spectrum so scientists use these to identify the different elements present in stars and galaxies.