Satellites and moons
3 marks · EasyA planet and an artificial satellite are shown below.
Draw an arrow on the diagram to show the direction of the force acting on the satellite.
Explain why this force is always directed towards the planet.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Arrow from the satellite towards the planet's centre. · must show Arrow from satellite to planet
(b) Gravity always pulls objects towards the centre of the planet, providing the force needed to keep the satellite in orbit.
Must show: Arrow from satellite to planet
Common mistakes: Arrow drawn tangentially; Arrow away from planet
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Draws arrow correctly from the satellite towards the planet centre.
M1 (b) · 1 mark · States force is gravity or gravitational attraction.
A1 (b) · 1 mark · Explains gravity always acts towards the centre of the planet (centre-seeking).
Worked solution
The force on the satellite is always towards the planet. This keeps the satellite moving in a circle.