What is the mass of the star? you are the science officer on a visit to a distant solar system. prior to landing on a planet you measure its diameter to be 1.8×107m and its rotation period to be 22.3 hours . you have previously determined that the planet orbits 2.2×1011m from its star with a period of 422 earth days. once on the surface you find that the free-fall acceleration is 12.2m/s2.

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.