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13. Gravitational fields
A section of Physics, 9702
Listing 10 of 105 questions
A gravitational field may be represented by lines of gravitational force. State what is meant by a line of gravitational force. By reference to lines of gravitational force near to the surface of the Earth, explain why the gravitational field strength g close to the Earth’s surface is approximately constant. The Moon may be considered to be a uniform sphere of diameter 3.4 × 103 km and mass 7.4 × 1022 kg. The Moon has no atmosphere. During a collision of the Moon with a meteorite, a rock is thrown vertically up from the surface of the Moon with a speed of 2.8 km s–1. Assuming that the Moon is isolated in space, determine whether the rock will travel out into distant space or return to the Moon’s surface.
9702_s18_qp_42
THEORY
2018
Paper 4, Variant 2
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State what is meant by a field of force. Define gravitational field strength. An isolated planet may be assumed to be a uniform sphere of radius 3.39 × 106 m with its mass of 6.42 × 1023 kg concentrated at its centre. Calculate the gravitational field strength at the surface of the planet. field strength = N kg–1 Calculate the height above the surface of the planet in at which the gravitational field strength is 1.0% less than its value at the surface of the planet. height = m
9702_w20_qp_41
THEORY
2020
Paper 4, Variant 1
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State what is meant by a field of force. Define gravitational field strength. An isolated planet may be assumed to be a uniform sphere of radius 3.39 × 106 m with its mass of 6.42 × 1023 kg concentrated at its centre. Calculate the gravitational field strength at the surface of the planet. field strength = N kg–1 Calculate the height above the surface of the planet in at which the gravitational field strength is 1.0% less than its value at the surface of the planet. height = m
9702_w20_qp_43
THEORY
2020
Paper 4, Variant 3
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Define gravitational field. A spherical planet can be considered as a point mass at its centre. On , draw gravitational field lines outside the planet to represent the gravitational field due to the planet. planet A satellite is in a circular orbit around the planet. Explain, with reference to your answer in , why the path of the satellite is circular. An object rests on the surface of the Earth at the Equator. The radius of the Earth is 6.4 × 106 m. Determine the centripetal acceleration of the object. centripetal acceleration = m s–2 Describe how the two forces acting on the object give rise to this centripetal acceleration. You may draw a diagram if you wish.
9702_w22_qp_42
THEORY
2022
Paper 4, Variant 2
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State what is meant by a line of force in a gravitational field. By reference to the pattern of the lines of gravitational force near to the surface of the Earth, explain why the acceleration of free fall near to the Earth’s surface is approximately constant. The Moon may be considered to be a uniform sphere that is isolated in space. It has radius 1.74 × 103 km and mass 7.35 × 1022 kg. Calculate the gravitational field strength at the Moon’s surface. gravitational field strength = N kg–1 A satellite is in a circular orbit about the Moon at a height of 320 km above its surface. Calculate the time for the satellite to complete one orbit of the Moon. time = s
9702_m18_qp_42
THEORY
2018
Paper 4, Variant 2
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Explain why the gravitational potential near to a point mass is negative. A planet may be assumed to be a uniform sphere. It has gravitational potential φ at distance r from the centre of the planet. The variation with 1 r of φ is shown in . –2.4 –2.0 –1.6 –1.2 –0.8 –0.4 / 108 J kg–1 0.5 1.0 1.5 2.0 2.5 3.0 / 10–8 m–1 3.5 4.0 φ r Show that the mass of the planet is 8.8 × 1025 kg. The period of rotation of the planet is 0.72 Earth days. A satellite in orbit around the planet remains above the same point on the surface of the planet. Use the mass of the planet in to determine the radius R of the orbit of the satellite. R = m The speed of the satellite in is 8400 m s–1. The mass of the satellite is 1200 kg. Determine the additional energy required to move the satellite from its orbit to infinity. energy required = J
9702_m24_qp_42
THEORY
2024
Paper 4, Variant 2
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Questions Discovered
105