2018年USAAAO短问题第9道

英文题目

9. [5 pt] Solar wind consists of protons that fly with the speed of 300 km/s and they fill the space of interplanetary matter around Earth with $$10 particles/cm^3$$ . With what force is this “wind” hitting the Moon? Recall that mass of a proton is $$mp = 1.610^{−24} g$$. Radius of the Moon is $$R_m=1737 km$$.