Astrophysics

Question 1

The universe is

Answer 1

a large collection of billions of galaxies

Question 2

A galaxy is

Answer 2

a large collection of billions of stars

Question 3

A solar system is

Answer 3

a collection of planets orbiting a common star

Question 4

Our solar system is

Answer 4

the Milky Way galaxay

Question 5

Gravitational field strength is

Answer 5

force per unit mass on a body in a gravitational field

Question 6

Gravitational field strength units

Answer 6

Newtons per kilogram (N/kg)

Question 7

Weight (W) equals

Answer 7

mass x gravitational field strength (mg)

Question 8

Gravitational force enables…

Answer 8

…bodies to orbit around another body.

Question 9

Moons orbit

Answer 9

planets

Question 10

Planets and comets orbit

Answer 10

the sun

Question 11

Orbital paths or moons and planets are

Answer 11

slightly elliptical

Question 12

Orbital speeds of moons and planets are

Answer 12

nearly constant

Question 13

Orbital paths of comets are

Answer 13

highly elliptical

Question 14

Artificial satellites orbit

Answer 14

the earth

Question 15

Orbital speed equals

Answer 15

(2 x pi x orbital radius ) / time period

V = (2 pi r)/T

Question 16

Nearer a star comet’s speed is

Answer 16

greater, because the ice inside them melts as they get closer and warmer, causing their mass to decrease

Question 17

Stella Evolution
1. A star begins as
2. The particles experience
3. They continue to clump until
4. Hydrogen nuclei
5. This outward pressure
6. The star is now
7. and called a
8. Eventually the hydrogen
9. If the mass of the collapsed star is similar to the sun
10. If the mass of the collapsed star is greater than the sun

Answer 17

1. a cloud of dust and gas called a nebula
2. a weak attraction to each other a begin to clump together
3. the pressure and temperature are great enough for nuclear fusion
4. Fuse together to form helium nuclei which releases a large amount of energy and causes great outward pressure.
5. balances with the inward pressure due to gravity
6. stable
7. main sequence star
8. in the star is used up so there is no longer enough outward pressure from the nuclear fusion and it collapses.
9. it becomes a red giant, then a white dwarf and finally it cools to a black dwarf
10. It expands and becomes a red super giant, before exploding in a supernova. What remain is a neutron star or (if it was exceptionally massive) a black hole

Question 18

Stars can be classified according to

Answer 18

colour

Question 19

The colour of a star is related to

Answer 19

its surface temperature

Question 20

Hotter stars are

Answer 20

bluer

Question 21

Cooler stars are

Answer 21

redder