NESA Physics Motion in Gravitational Fields

5 sample questions with marking guides and sample answers · Avg. score: 61.8%

Q18
2025
NESA
1 mark
Q18
1 mark

The escape velocity from the surface of a planet, which has no atmosphere, is vv. A mass is launched at 45∘45^\circ to the planet's surface at vv.

What will be the subsequent motion of the mass?

A

A circular orbit around the planet

B

An elliptical orbit around the planet

C

A parabolic trajectory, returning to land with velocity vv

D

A trajectory reaching zero velocity at an infinite distance

Q14
2023
NESA
1 mark
Q14
1 mark

Planet X has a mass 4 times that of Earth and a radius 3 times that of Earth. The escape velocity at the surface of Earth is 11.2 km s−1^{-1}.

What is the escape velocity at the surface of planet X?

A

8.40 km s−1^{-1}

B

9.70 km s−1^{-1}

C

12.9 km s−1^{-1}

D

14.9 km s−1^{-1}

Q24
2025
NESA
3 marks
Q24
3 marks

Two satellites, AA and BB, are in stable circular orbits around the Earth. The radius of satellite AA's orbit is three times that of satellite BB's orbit. Both satellites have the same kinetic energy.

Show that the mass of AA is three times the mass of BB.

Q23
2023
NESA
7 marks
Q23

The James Webb Space Telescope (JWST) has a mass of 6.1×103 kg6.1 \times 10^{3}\ \text{kg} and orbits the Sun at a distance of approximately 1.52×1011 m1.52 \times 10^{11}\ \text{m}.

Q23a
2 marks

The Sun has a mass of 1.99×1030 kg1.99 \times 10^{30}\ \text{kg}.

Calculate the magnitude of gravitational force the Sun exerts on the JWST.

Q23b
3 marks

The telescope is sensitive to wavelengths from 6.0×10−7 m6.0 \times 10^{-7}\ \text{m} to 2.8×10−5 m2.8 \times 10^{-5}\ \text{m}.

What is the minimum photon energy that it can detect?

Q23c
2 marks

The JWST observed an exoplanet emitting a peak wavelength of 1.14×10−5 m1.14 \times 10^{-5}\ \text{m}.

Calculate the temperature of the exoplanet.

Q4
2024
QCAA
Paper 2
4 marks
Q4
4 marks

Explain how a satellite can be accelerating yet maintain a constant speed in a circular orbit around a planet.

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s orbit is three times that of satellite $B

NESA Physics Motion in Gravitational Fields

5 sample questions with marking guides and sample answers · Avg. score: 61.8%

Q18
2025
NESA
1 mark
Q18
1 mark

The escape velocity from the surface of a planet, which has no atmosphere, is vv. A mass is launched at 45∘45^\circ to the planet's surface at vv.

What will be the subsequent motion of the mass?

A

A circular orbit around the planet

B

An elliptical orbit around the planet

C

A parabolic trajectory, returning to land with velocity vv

D

A trajectory reaching zero velocity at an infinite distance

Q14
2023
NESA
1 mark
Q14
1 mark

Planet X has a mass 4 times that of Earth and a radius 3 times that of Earth. The escape velocity at the surface of Earth is 11.2 km s−1^{-1}.

What is the escape velocity at the surface of planet X?

A

8.40 km s−1^{-1}

B

9.70 km s−1^{-1}

C

12.9 km s−1^{-1}

D

14.9 km s−1^{-1}

Q24
2025
NESA
3 marks
Q24
3 marks

Two satellites, AA and BB, are in stable circular orbits around the Earth. The radius of satellite AA's orbit is three times that of satellite BB's orbit. Both satellites have the same kinetic energy.

Show that the mass of AA is three times the mass of BB.

Q23
2023
NESA
7 marks
Q23

The James Webb Space Telescope (JWST) has a mass of 6.1×103 kg6.1 \times 10^{3}\ \text{kg} and orbits the Sun at a distance of approximately 1.52×1011 m1.52 \times 10^{11}\ \text{m}.

Q23a
2 marks

The Sun has a mass of 1.99×1030 kg1.99 \times 10^{30}\ \text{kg}.

Calculate the magnitude of gravitational force the Sun exerts on the JWST.

Q23b
3 marks

The telescope is sensitive to wavelengths from 6.0×10−7 m6.0 \times 10^{-7}\ \text{m} to 2.8×10−5 m2.8 \times 10^{-5}\ \text{m}.

What is the minimum photon energy that it can detect?

Q23c
2 marks

The JWST observed an exoplanet emitting a peak wavelength of 1.14×10−5 m1.14 \times 10^{-5}\ \text{m}.

Calculate the temperature of the exoplanet.

Q4
2024
QCAA
Paper 2
4 marks
Q4
4 marks

Explain how a satellite can be accelerating yet maintain a constant speed in a circular orbit around a planet.

Frequently Asked Questions

How many NESA Physics questions cover Motion in Gravitational Fields?
AusGrader has 57 NESA Physics questions on Motion in Gravitational Fields, all with instant AI grading and detailed marking feedback.

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s orbit. Both satellites have the same kinetic energy.\\n\\nShow that the mass of $A$ is three times the mass of $B$.\",\"marks\":3,\"questionType\":\"short_answer\",\"mcOptions\":null,\"rubric\":{\"sampleAnswer\":\"$\\n\\\\begin{align*}\\nF_C &= F_G\\\\\\\\\\n\\\\frac{mv^2}{r} &= \\\\frac{GMm}{r^2}\\\\\\\\\\nmv^2 &= \\\\frac{GMm}{r}\\\\\\\\\\n\\\\frac{1}{2}mv^2 &= \\\\frac{GMm}{2r}\\\\\\\\\\n\\\\therefore \\\\frac{G M m_A}{2 r_A} &= \\\\frac{G M m_B}{2 r_B}\\n\\\\end{align*}\\n$\\n\\nSubstitute $r_A = 3r_B$:\\n$\\n\\\\frac{3r_B}{r_B} = \\\\frac{m_A}{m_B} = 3\\n$\\n$\\\\therefore m_A = 3m_B$\",\"mcExplanations\":null,\"columns\":[{\"name\":\"Response\",\"isMarkingBands\":true,\"criteria\":[{\"descriptor\":\"Shows all relevant steps to determine the mass ratio\",\"marks\":3},{\"descriptor\":\"Makes progress towards determining mass ratio\",\"marks\":2},{\"descriptor\":\"Provides some relevant information\",\"marks\":1},{\"descriptor\":\"None of the above\",\"marks\":0}]}]}}]},{\"questionNumber\":23,\"year\":2023,\"paper\":null,\"authorName\":\"NESA\",\"calculatorAllowed\":true,\"inlineStimulus\":[{\"part\":null,\"text\":\"The James Webb Space Telescope (JWST) has a mass of $6.1 \\\\times 10^{3}\\\\ \\\\text{kg}$ and orbits the Sun at a distance of approximately $1.52 \\\\times 10^{11}\\\\ \\\\text{m}$.\"}],\"parts\":[{\"partLabel\":\"a\",\"questionText\":\"The Sun has a mass of $1.99 \\\\times 10^{30}\\\\ \\\\text{kg}$.\\n\\nCalculate the magnitude of gravitational force the Sun exerts on the JWST.\",\"marks\":2,\"questionType\":\"short_answer\",\"mcOptions\":null,\"rubric\":{\"sampleAnswer\":\"$\\n\\\\begin{align*}\\nF &= \\\\frac{GMm}{r^2}\\\\\\\\\\n&= \\\\frac{6.67 \\\\times 10^{-11} \\\\times 1.99 \\\\times 10^{30} \\\\times 6.1 \\\\times 10^3}{(1.52 \\\\times 10^{11})^2}\\\\\\\\\\n&= 35 \\\\text{ N}\\n\\\\end{align*}\\n$\",\"mcExplanations\":null,\"columns\":[{\"name\":\"Response\",\"isMarkingBands\":true,\"criteria\":[{\"descriptor\":\"Calculates the magnitude of gravitational force\",\"marks\":2},{\"descriptor\":\"Provides some relevant information\",\"marks\":1},{\"descriptor\":\"None of the above\",\"marks\":0}]}]}},{\"partLabel\":\"b\",\"questionText\":\"The telescope is sensitive to wavelengths from $6.0 \\\\times 10^{-7}\\\\ \\\\text{m}$ to $2.8 \\\\times 10^{-5}\\\\ \\\\text{m}$.\\n\\nWhat is the minimum photon energy that it can detect?\",\"marks\":3,\"questionType\":\"short_answer\",\"mcOptions\":null,\"rubric\":{\"sampleAnswer\":\"$\\n\\\\begin{align*}\\nE &= hf\\\\\\\\\\n&= \\\\frac{hc}{\\\\lambda}\\\\\\\\\\n&= \\\\frac{6.626 \\\\times 10^{-34} \\\\times 3 \\\\times 10^8}{2.8 \\\\times 10^{-5}}\\\\\\\\\\n&= 7.1 \\\\times 10^{-21} \\\\text{ J}\\n\\\\end{align*}\\n$\",\"mcExplanations\":null,\"columns\":[{\"name\":\"Response\",\"isMarkingBands\":true,\"criteria\":[{\"descriptor\":\"Calculates the minimum photon energy the telescope can detect\",\"marks\":3},{\"descriptor\":\"Provides some correct steps in calculating the minimum photon energy\",\"marks\":2},{\"descriptor\":\"Provides some relevant information\",\"marks\":1},{\"descriptor\":\"None of the above\",\"marks\":0}]}]}},{\"partLabel\":\"c\",\"questionText\":\"The JWST observed an exoplanet emitting a peak wavelength of $1.14 \\\\times 10^{-5}\\\\ \\\\text{m}$.\\n\\nCalculate the temperature of the exoplanet.\",\"marks\":2,\"questionType\":\"short_answer\",\"mcOptions\":null,\"rubric\":{\"sampleAnswer\":\"$\\n\\\\begin{align*}\\n\\\\lambda &= \\\\frac{b}{T}\\\\\\\\\\nT &= \\\\frac{b}{\\\\lambda}\\\\\\\\\\n&= \\\\frac{2.898 \\\\times 10^{-3}}{1.14 \\\\times 10^{-5}}\\\\\\\\\\n&= 254 \\\\text{ K}\\n\\\\end{align*}\\n$\",\"mcExplanations\":null,\"columns\":[{\"name\":\"Response\",\"isMarkingBands\":true,\"criteria\":[{\"descriptor\":\"Calculates the temperature of the exoplanet\",\"marks\":2},{\"descriptor\":\"Provides some relevant information\",\"marks\":1},{\"descriptor\":\"None of the above\",\"marks\":0}]}]}}]},{\"questionNumber\":4,\"year\":2024,\"paper\":2,\"authorName\":\"QCAA\",\"calculatorAllowed\":true,\"inlineStimulus\":null,\"parts\":[{\"partLabel\":null,\"questionText\":\"Explain how a satellite can be accelerating yet maintain a constant speed in a circular orbit around a planet.\",\"marks\":4,\"questionType\":\"short_answer\",\"mcOptions\":null,\"rubric\":{\"sampleAnswer\":\"The satellite has **inertia** and, in the absence of the **planet**, would continue in a straight line with the same speed until acted upon by an unbalanced force.\\n\\nWhen the **planet's gravitational force pulls the satellite towards it (perpendicular to the satellite's motion)**, the satellite changes direction and thus accelerates towards the planet, but its speed does not change.\\n\\nAs a result, the satellite continues to move ‘forward’, but the planet’s gravitational force pulls the satellite towards it. So the resultant motion is that the satellite has a constant speed (not velocity as direction is changing) travelling in a circle around the planet.\",\"mcExplanations\":null,\"columns\":[{\"name\":\"Response\",\"isMarkingBands\":false,\"criteria\":[{\"descriptor\":\"describes inertia of satellite\",\"marks\":1},{\"descriptor\":\"identifies that planet provides a centripetal force\",\"marks\":1},{\"descriptor\":\"identifies that the centripetal force is perpendicular to the satellites motion\",\"marks\":1},{\"descriptor\":\"explains that changing direction means change in velocity which is acceleration\",\"marks\":1}]}]}}]}]}")

NESA Physics Motion in Gravitational Fields

5 sample questions with marking guides and sample answers · Avg. score: 61.8%

Q18
2025
NESA
1 mark
Q18
1 mark

The escape velocity from the surface of a planet, which has no atmosphere, is vv. A mass is launched at 45∘45^\circ to the planet's surface at vv.

What will be the subsequent motion of the mass?

A

A circular orbit around the planet

B

An elliptical orbit around the planet

C

A parabolic trajectory, returning to land with velocity vv

D

A trajectory reaching zero velocity at an infinite distance

Q14
2023
NESA
1 mark
Q14
1 mark

Planet X has a mass 4 times that of Earth and a radius 3 times that of Earth. The escape velocity at the surface of Earth is 11.2 km s−1^{-1}.

What is the escape velocity at the surface of planet X?

A

8.40 km s−1^{-1}

B

9.70 km s−1^{-1}

C

12.9 km s−1^{-1}

D

14.9 km s−1^{-1}

Q24
2025
NESA
3 marks
Q24
3 marks

Two satellites, AA and BB, are in stable circular orbits around the Earth. The radius of satellite AA's orbit is three times that of satellite BB's orbit. Both satellites have the same kinetic energy.

Show that the mass of AA is three times the mass of BB.

Q23
2023
NESA
7 marks
Q23

The James Webb Space Telescope (JWST) has a mass of 6.1×103 kg6.1 \times 10^{3}\ \text{kg} and orbits the Sun at a distance of approximately 1.52×1011 m1.52 \times 10^{11}\ \text{m}.

Q23a
2 marks

The Sun has a mass of 1.99×1030 kg1.99 \times 10^{30}\ \text{kg}.

Calculate the magnitude of gravitational force the Sun exerts on the JWST.

Q23b
3 marks

The telescope is sensitive to wavelengths from 6.0×10−7 m6.0 \times 10^{-7}\ \text{m} to 2.8×10−5 m2.8 \times 10^{-5}\ \text{m}.

What is the minimum photon energy that it can detect?

Q23c
2 marks

The JWST observed an exoplanet emitting a peak wavelength of 1.14×10−5 m1.14 \times 10^{-5}\ \text{m}.

Calculate the temperature of the exoplanet.

Q4
2024
QCAA
Paper 2
4 marks
Q4
4 marks

Explain how a satellite can be accelerating yet maintain a constant speed in a circular orbit around a planet.

Frequently Asked Questions

How many NESA Physics questions cover Motion in Gravitational Fields?
AusGrader has 57 NESA Physics questions on Motion in Gravitational Fields, all with instant AI grading and detailed marking feedback.

Ready to practise NESA Physics?

Get instant AI feedback on past exam questions, aligned to the syllabus

Start Practising Free