You toss a walnut at a speed of 15.0 m/s at an angle of 50.0∘ above the horizontal. The launch point is on the roof of a building that is 20.0 m above the ground.

a)How long after it is launched does the walnut reach the ground?

b)How far does the walnut travel horizontally from launch point to landing point?

c) What are the horizontal and vertical components of the walnut’s velocity just before it reaches the ground? Suppose that the +y-axis is directed upward and the +x-axis is directed horizontally from the launch point toward the landing point.

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.