How much weaker (or stronger) is the force of gravity acting upon a typical person at the surface of the Earth relative to the force of gravity acting upon M31 as it is pulled towards the Milky Way? [Recall that the mass and radius of the Earth are MEarth = 6 × 1024 kg and REarth = 6400 km, while M31 ∼ 4 × 1042 kg and MMW ∼ 2 × 1042 kg, with the two galaxies separated by roughly 2 × 1019 km. A typical person has a mass of 60 kg.]