motion in the universe Flashcards
(31 cards)
List the following objects in order of increasing size: Sun, Milky Way, Earth, Universe, Moon.
Moon (smallest), Earth, Sun, Milky Way, Universe (largest)
Define Universe.
The Universe is a large collection of billions of galaxies.
Define galaxy.
A galaxy is a large collection of billions of stars.
What is the difference between a galaxy and the Universe?
A galaxy is a large collection of stars, whereas the Universe is made up of billions of galaxies.
What is the Milky Way?
The Milky Way is a galaxy containing billions of stars, including our Sun.
Which galaxy is our Solar System located in?
Our Solar System is located in the Milky Way galaxy.
True or False? The Sun is at the centre of the Milky Way.
False. The Sun is at the centre of the Solar System.
Define weight.
Weight is the force acting on an object due to gravitational attraction.
What is the equation for weight?
The equation for weight is: W = mg
Where: W = weight (N), m = mass (kg), g = gravitational field strength (N/kg)
State the meaning of gravitational field strength.
Gravitational field strength is the strength of the gravitational pull exerted by an object on another object on or near its surface.
True or False? Gravitational field strength is constant at the surface of a given planet.
True.
On which planet in the Solar System would you weigh the heaviest?
You would weigh the heaviest on Jupiter, as this is the largest (most massive) planet.
In which direction does the gravitational force of an orbiting body act?
The gravitational force exerted on an orbiting body acts towards the centre of the larger body it is orbiting.
True or False? The larger the mass of a planet the greater its gravitational field strength.
True.
True or False? All objects in the Solar System orbit the Sun.
False. Planets, comets and asteroids orbit the Sun, whereas satellites orbit planets.
True or False? When planets and satellites orbit larger bodies, they move in approximately circular paths.
True.
Which type of object in the Solar System has the most elongated elliptical orbit?
Comets have the most elongated elliptical orbits in the Solar System.
True or False? The Sun is at the centre of an elliptical orbit.
False.
How does the orbital radius of a planet change with increasing distance from the Sun?
The orbital radius of a planet increases with increasing distance from the Sun.
How does the orbital period of a planet change with increasing distance from the Sun?
The orbital period of a planet increases with increasing distance from the Sun.
How does the orbital speed of a planet change with increasing distance from the Sun?
The orbital speed of a planet decreases as the distance from the Sun increases.
How does the speed of a comet change as it approaches the Sun?
The speed of a comet changes as it approaches the Sun because it speeds up.
Define the term orbital speed.
Orbital speed is the average speed of an object as it orbits around a larger object.
State the equation for calculating orbital speed in terms of distance and time.
The equation for calculating orbital speed is: speed = distance / time.
