Chapter 6 - Astronomy

Question 1

Difference between a planet and an asteroid?

Answer 1

Planets are bigger

Question 2

Difference between an asteroid and a comet?

Answer 2

• Comet has an icy surface

- Asteroids are rocky

Question 3

What shape is the Milky Way?

Answer 3

• Spiral

Question 4

What is the formula for orbital speed?

Answer 4

time period

Question 5

Telescope completes one orbit in 96 minutes.
The radius is 6960km
Calculate its orbital speed in m/s

Answer 5

(6960 times by 1000 = 696,000,0)
2 x π x 696,000,0
—————–
96 x 60

= 7592 m/s

Question 6

The Chandra Telescope also orbits the Earth, but does not move in a circular orbit.
Its distance from the Earth and its speed change as it orbits the Earth.
It travels fastest when it is closest to the Earth.
Use ideas about energy to explain why [3 marks]

Answer 6

• GPE reduces when closer;
• Therefore KE increases;
• because total energy conserved

Question 7

Explain why a comet travels fastest near the sun [1 mark]

Answer 7

• Closer to Sun

- Gravitational force strongest

Question 8

The gravitational field strength is smaller on the Moon than on the Earth.
Suggest why [1 mark]

Answer 8

Moon has less mass than Earth

Question 9

Example of an artificial satellite and a natural satellite [2 marks]

Answer 9

Natural - Moon

Artificial - Sat Nav Systems

Question 10

what is the universe [1 mark]

Answer 10

• a large collection of billions of galaxies

Question 11

What is a galaxy [1 mark]

Answer 11

• A large collection of billions of stars

Question 12

Where is the solar system [1 mark]

Answer 12

• Solar system is in the Milky Way galaxy

Question 13

What causes moons to orbit planets [1 mark]

Answer 13

• gravitational force

Question 14

What causes planets to orbit the sun [1 mark]

Answer 14

Gravitational force

Question 15

What causes artificial satellites to orbit the Earth [1 mark]

Answer 15

• gravitational force

Question 16

What causes comets to orbit the sun [1 mark]

Answer 16

• gravitational force