Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Astrophysics
156 practice questions
Topics covered
Practice questions
61–70 of 156
Question 61
2 marks · Normal
Answer and see the solution →Geostationary satellites have a much larger orbital radius than low orbit satellites. State and explain how the orbital speed of a geostationary satellite compares to that of a low orbit satellite.
Question 62
3 marks · Normal
Answer and see the solution →The Moon has an orbital radius of 384,000 km and takes 27.3 days to orbit Earth once. Calculate the average orbital speed of the Moon in km/s. (1 day = 86,400 s).
Question 63
1 mark · Normal
Answer and see the solution →Describe what would happen to a satellite if it slowed down in its orbit.
Question 64
4 marks · Easy
Answer and see the solution →The planet Venus and a space probe orbiting Earth both move in nearly circular orbits because of gravity.
(a)[1 mark]Name the force responsible for keeping Venus and the space probe in orbit.
(b)[2 marks]Explain why Venus moves faster in its orbit than Neptune does.
(c)[1 mark]State one difference between the orbit of the space probe and the orbit of a comet around the Sun.
Question 65
4 marks · Easy
Answer and see the solution →A satellite is placed in orbit at a height where the gravitational field strength is much smaller than on Earth’s surface.
(a)[2 marks]Explain why the satellite stays in orbit instead of falling straight towards the Earth.
(b)[2 marks]Calculate the orbital speed of the satellite if it travels along a circular path of radius m and completes one orbit in 24 hours. Give your answer in to two significant figures.
Question 66
4 marks · Easy
Answer and see the solution →The table below shows the gravitational field strength on the surface of different planets:
Planet Gravitational field strength (N/kg) Earth 10 Mars 4 Jupiter 23 Venus 9 (a)[1 mark]Which planet has the strongest gravitational field strength?
(b)[2 marks]A 60 kg object is placed on Mars. Calculate its weight on the surface of Mars.
(c)[1 mark]Explain why the weight of an object on Jupiter is more than that on Earth.
Question 67
4 marks · Easy
Answer and see the solution →Halley's Comet has an orbit that brings it close to the Sun, then takes it far out into the solar system. Meanwhile, Earth’s Moon orbits Earth at nearly constant speed.
(a)[2 marks]Describe the main difference in the orbit of a comet compared with that of a moon.
(b)[1 mark]State what happens to the speed of the comet as it moves closer to the Sun.
(c)[1 mark]Explain your answer to part b using ideas about forces in the solar system.
Question 68
6 marks · Normal
Answer and see the solution →The planet Mars and one of its artificial satellites both move in orbits around different objects. The table below gives the average orbital radius and time period of Mars around the Sun, and of a satellite around Mars.
(a)[1 mark]Orbital data for Mars and its satellite Object Orbits Average Orbital Radius (km) Time Period (days) Mars Sun 227,900,000 687 Satellite Mars 6,000 0.32 (b)[1 mark]State the name of the force responsible for keeping both Mars and the satellite in their respective orbits.
(c)[2 marks]Explain why the time period of orbit is much greater for Mars than for its satellite, even though both are in orbit due to the same force.
(d)[2 marks]Calculate the orbital speed of the artificial satellite around Mars. Give your answer in km/s. Use the formula: speed = (2 ) / , where is the orbital radius and is the time period in seconds.
Question 69
5 marks · Normal
Answer and see the solution →Consider a comet with a highly elliptical orbit around the Sun, and a moon with a nearly circular orbit around a planet.
(a)[2 marks]State two differences between the orbit of a comet and that of a moon in our solar system.
(b)[2 marks]Explain why the speed of a comet changes as it moves along its orbit, while the speed of a moon remains nearly constant.
(c)[1 mark]The average orbital radius of the moon is 400,000 km. If it takes 28 days to complete one orbit, calculate the average orbital speed of the moon. Give your answer in km/s.
Question 70
5 marks · Normal
Answer and see the solution →The table below shows some data about gravitational field strengths for two planets and their effect on the orbits of their moons.
(a)[1 mark]Planetary Data Planet Mass (Earth=1.0) Radius (Earth=1.0) Gravitational Field Strength (N/kg) Earth 1.0 1.0 10 Jupiter 320 11 23 (b)[2 marks]Explain, using the data, why gravity is stronger at the surface of Jupiter than at the surface of Earth.
(c)[2 marks]The moon of Jupiter orbits at an average radius of 422,000 km and completes one orbit in 1.8 days. Calculate the average orbital speed of this moon in km/s (show all working).