#8.2
know that:
- the universe is a large collection of billions of galaxies
- a galaxy is a large collection of billions of stars
- our solar system is in the Milky Way galaxy.
#8.3
understand why gravitational field strength, g, varies and know that it is different on other planets and the Moon from that on the Earth
#8.4
explain that gravitational force:
- causes moons to orbit planets
- causes the planets to orbit the Sun
- causes artificial satellites to orbit the Earth
- causes comets to orbit the Sun.
#8.5
describe the differences in the orbits of comets, moons and planets
#8.6
use the relationship between orbital speed, orbital radius and time period:
\(\text{orbital speed} = \dfrac{\text{2 × π × \text{orbital radius}}}{\text{time period}}\)
\(v = \dfrac{2 × π × r}{T}\)