Practice D.1 Gravitational fields with authentic IB Physics exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like mechanics, thermodynamics, and waves. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
A satellite orbits a planet of mass at a radius of from the planet’s centre. The satellite has a mass of .
Calculate the gravitational force acting on the satellite.
Determine the orbital speed of the satellite.
Calculate the total energy of the satellite in its orbit.
Explain how the energy of the satellite would change if its orbit gradually decays.
The diagram shows two point masses: mass and mass . Point lies between them, at a distance from mass and from mass B.
State the condition for the net gravitational field at point to be zero.
Show that the magnitudes of the gravitational fields due to each mass at point are equal.
If and , calculate the magnitude of the gravitational field at due to mass .
If a test mass were placed at point , describe qualitatively what would happen if it were slightly displaced toward mass A.
The Moon orbits the Earth at an average distance of . The mass of the Earth is and .
State the direction of the gravitational field produced by the Earth.
Calculate the gravitational field strength at the Moon’s orbit due to the Earth.
Explain why the Moon remains in orbit despite this weak field.
A spacecraft of mass is in orbit at an altitude of above the surface of Earth. Earth's radius is , and its mass is . .
Calculate the orbital speed of the spacecraft.
Determine the total mechanical energy of the spacecraft in orbit.
Calculate the difference in gravitational potential energy between the spacecraft at orbit and on the surface of the Earth.
If the spacecraft is to escape Earth’s gravity from orbit, calculate the additional speed required (i.e., the difference between escape speed and orbital speed).
Explain why escape speed is independent of the mass of the escaping object.
A satellite is in circular orbit above the surface of Earth. The radius of Earth is , and Earth’s mass is .
Calculate the distance from the centre of the Earth to the satellite.
Determine the gravitational field strength at the satellite’s altitude.
Calculate the orbital speed required for the satellite to stay in circular orbit.
Explain why the gravitational field strength decreases with altitude.
A hypothetical planet X has twice the mass of Earth and a radius 1.5 times that of Earth. A spacecraft of mass is to be launched from the surface of planet X into a circular orbit at an altitude of above its surface. The mass of Earth is and its radius is .
Calculate the gravitational field strength at the surface of planet X.
Determine the orbital radius of the spacecraft.
Calculate the orbital speed required for circular motion.
Calculate the total mechanical energy of the spacecraft in orbit.
Discuss how the energy required to launch the spacecraft into this orbit compares with the same operation on Earth.
A spacecraft of mass is moving in the gravitational field of a planet of mass . At a particular point A, it is located from the centre of the planet. Another point B is located at a radial distance of .
Calculate the gravitational potential at point A.
Calculate the gravitational potential at point B.
Determine the work done by the gravitational field in moving the spacecraft from point B to point A.
Calculate the average gravitational field strength between points A and B using the potential gradient definition.
Explain how the direction of the gravitational field is related to the potential gradient and equipotential surfaces.
Two identical asteroids, each of mass , are initially at rest and separated by in deep space.
Calculate the initial gravitational potential energy of the system.
Determine the gravitational potential at the midpoint between the two asteroids.
Calculate the gravitational field strength at the midpoint between the two asteroids.
Explain whether a test mass placed at the midpoint would accelerate and in which direction.
A test mass is moved along a radial line in the gravitational field of a large isolated mass . It moves from point X at to point Y at .
Calculate the gravitational potential at points X and Y.
Determine the work done in moving the test mass from X to Y.
Use the gravitational potential gradient to estimate the average field strength between X and Y.
Sketch the gravitational potential versus radial distance from the mass. Indicate on the graph the direction of increasing potential and the relationship to field strength.
Which of the following correctly describes the force acting between two point masses due to gravity?