[填空题]
You are explaining why astronaztj so 9*jvy57:r+2omsu tzh, uts feel weightless wh7qkjdltd3s ( */ h2fpcile orbiting in the space shuttle. Your friendsh/2q d3 s(k *plf7tjdc respond that they thought gravity was just a lot weaker up there. Convince them and yourself that it isn’t so by calculating the acceleration of gravity 250 km above the Earth’s surface in terms of g.
