Our solar system

Figure 11 gives the values of gravitational field strength, g, on the surfaces of Earth, the Moon and Mars.

Calculate the ratio

A person has a weight of 730 N on Earth.

Calculate the person’s weight on the Moon, using information from Figure 11.

The gravitational field strength, g, is different on the surfaces of Earth, the Moon and Mars.

Explain why this is the case.

Asteroids have elliptical (oval) orbits around

*(c) Scientists have been searching beyond the Solar System to find planets where life could exist.

One requirement for life to exist on a planet is that there is water on the surface of the planet.

The planets where surface water could exist are in a region called the habitable zone.

Figure 12 is a diagram showing our Sun, with its five closest planets, and a more distant star with three of its planets labelled A, B and C. The habitable zone is shaded.

(Source adapted from: https://www.researchgate.net/publication/23993674_Darwin_-A_ Mission_to_Detect_and_Search_for_Life_on_Extrasolar_Planets/figures?lo=1)

Discuss the chance of life existing on the planets shown in Figure 12.

Your answer should refer to

• the five planets shown from our Solar System, giving the names of P, Q and R.

• the three planets, A, B and C, orbiting the more distant star.

Figure 15 shows an artificial satellite in orbit around the Earth.

Which of these shows the direction of the force that keeps the satellite in orbit around the Earth?

The satellite travels at a constant speed around the Earth.

Explain why the satellite is accelerating even though it travels at a constant speed.

The Hubble Space Telescope is an artificial satellite in orbit about 500 km above the Earth’s surface.

This telescope is used to observe the light from very distant objects in the Universe.

Explain why the Hubble Space Telescope must be high above the Earth’s surface to make its observations.

There are many other artificial satellites in orbit around the Earth.

Figure 16 shows the time taken to complete one orbit for satellites at different heights above the Earth’s surface.

time to complete one orbit in minutes

Figure 16

Describe the relationship shown in Figure 16.

*(d) A long time ago, many people thought that the objects seen in the sky were arranged as shown in Figure 17.

Compare the arrangement shown in Figure 17 with what we now know about the Solar System.

Your answer should refer to

• the objects that are in the Solar System

• how these objects are arranged.

You may draw a diagram to help your answer.

A rock on the surface of the Earth has a mass of 12 kg.

Calculate the weight of this rock on the surface of the Earth.

The gravitational field strength on the surface of the Earth is 10 N/kg.

Use the equation

weight on the Earth =_........

The weight of the same rock on the surface of the Moon is 20 N.

Calculate the gravitational field strength on the surface of the Moon.

gravitational field strength on the Moon_........

*(b) Describe the Solar System in terms of the Sun, the planets, and the other objects which move in the Solar System.

Your answer should include the patterns of movement of the planets and the other objects in the Solar System.

You may draw a labelled diagram if it helps your answer.

The Sun is at the centre of our Solar System.

The planets orbit the Sun.

Which planet is nearest to the Sun?

The Moon orbits the Earth.

Which of these describes the Moon?

Any object weighs less on the Moon than it does on the Earth.

The gravitational field strength on the Moon is different from the gravitational field strength on the Earth.

Suggest two reasons why the gravitational field strength on the Moon is different from the gravitational field strength on the Earth.

The gravitational field strength on the Moon is 1.6 N/kg. The mass of a rock on the Moon is 6.0 kg.

Calculate the weight of this rock on the Moon.

State the unit of weight.

Use the equation

weight = mass gravitational field strength

The Asteroid Belt is part of our Solar System.

Vesta is an asteroid in the Asteroid Belt.

Vesta orbits the Sun between the orbits of

Vesta has an orbital speed of 1.9 × 10⁴ m/s.

Vesta travels a distance of 2.2 × 10¹² m when it orbits the Sun once.

Calculate the time taken for Vesta to orbit the Sun once.

Explain why Vesta is accelerating even when it is travelling at a constant speed.

Energy is transferred from the Sun to Vesta by radiation.

Explain why the temperature on Vesta does not continue to rise, even though it is absorbing energy from the Sun.

The distance between Vesta and the Sun is 2.4 AU.

1 AU is the distance between the Earth and the Sun.

The intensity of the Sun’s radiation reaching the Earth is 1400 W/m².

1 W = 1 J/s

The intensity of the Sun’s radiation at a distance, d, from the Sun is given by the equation

where K always has the same value.

State the unit of K.

Calculate the intensity of the radiation from the Sun at Vesta.

Which of these planets is at the greatest distance from the Sun?

Use words from the box to complete the following sentences.

Saturn is a_........ .

The Moon is a_........ .

Halley’s Comet orbits a_........ .

Figure 3 shows a Mars Exploration Rover.

The mass of the rover is 190 kg.

The gravitational field strength on Earth is 10 N / kg.

Calculate the weight of the rover on Earth.

Use the equation

weight = mass × gravitational field strength

The weight of the rover on Mars is 700 N.

Calculate the gravitational field strength on Mars.

gravitational field strength on Mars =_........ N / kg

Which lens is a converging lens with the greatest power?

The equation that relates the power of a lens to the focal length of the lens is

The power of a lens is 5 dioptres.

Use the equation to calculate the focal length of the lens in cm.

Figure 3 shows a semicircular glass block.

Figure 3

Describe how a student could use the semicircular glass block and other apparatus to determine the critical angle for a glass‑air boundary.

You should add to the diagram in Figure 3 to help with your answer.

A long time ago, scientists believed that the Earth was at the centre of the Solar System.

Evidence has since proved that the Sun is at the centre of the Solar System.

State one other idea about the Solar System that has changed over time.

Figure 4 shows data for some of the planets of the Solar System.

distance from the Sun in millions of km

Figure 4

Ceres is an asteroid that orbits the Sun between Mars and Jupiter. It takes Ceres 4.6 Earth years to make one orbit of the Sun.

Use the graph to estimate the distance of Ceres from the Sun.

Show your working.

distance of Ceres from the Sun =_........ millions of km

Figure 12 is a diagram showing a lens, with some light rays passing through it.

This diagram shows a

Which length, labelled on Figure 12, shows the focal length of the lens?

Calculate the power of a lens of focal length 17 cm.

Use the equation

Give the answer to 2 significant figures.

power =_........ dioptres

*(c) More than two thousand years ago the Earth was believed to be at the centre of the universe as shown in Figure 13.

The planets, the Moon and the Sun were believed to be in orbit around the Earth.

In 1543 Nicolaus Copernicus proposed that the Earth was a planet, and that the Earth and the other planets orbit around the Sun. This model is shown in Figure 14.

Discuss how evidence has changed our views of the universe.