A rock R, with mass $1.0 \times 10^{27}\ \text{kg}$, is far from a star S and is moving at a speed of $1.0 \times 10^{4}\ \text{m s}^{-1}$. The star has mass $1.0 \times 10^{30}\ \text{kg}$. The rock moves round the star along the path shown, causing it to reverse the direction of its motion and, when it is once more far from the star, to have the same speed as at the start. Which statement is correct?
- AThe change in the momentum of S is in the direction of arrow X.
- BThe change in the velocity of S is approximately $20\ \text{m s}^{-1}$.
- CThe magnitude of the change of momentum of R is $10^{3}$ times greater than the magnitude of the change of momentum of S.
- DThe momentum of R does not change.