1. A moving plane drop of a package at a speed of 30 m/s. What is the vertical velocity of the package after 30seconds?
2. From a tall building, a girl throws a piece of paper at a velocity of 15m/s. What is the
horizontal velocity of the paper after 8 seconds?
3. At what time will a ball thrown horizontally reach its velocity at 22.2 m/s downwards?
4. A stone is thrown at a speed of 12m/s. What is the horizontal velocity after 10 seconds?
5. A stone is thrown at a speed of 18m/s. What is the vertical velocity after 8 seconds?

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.