On Fig. 9.1, draw the orbits of Mercury and Mars. Label each orbit.
Explain why the comet at position 3 cannot be seen from Earth when Earth is at position 5.
A force keeps the comet moving in orbit around the Sun. State the name of the force acting on the comet.
Four comet positions are shown in Fig. 9.1. On Fig. 9.1, indicate the direction of the force acting on the comet at each of the four positions shown.
Describe how the strength of the force acting on the comet changes as the comet moves from position 1 through position 3 to position 4. Explain your answer.
In the same time, Earth makes more trips around the Sun than Jupiter. Calculate the number of orbits that Earth makes around the Sun in the time that Jupiter makes one orbit. Show your working.