A girl pushes herself up a steep ramp in her wheelchair. She gains a vertical distance of
25.8 m when she reaches the top of the ramp.
She turns around and coasts back down the ramp.
If the combined mass of the girl and her wheelchair
is 64.6 kg, what would be her coasting speed at the
bottom of the ramp? Show all your work.

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.

Describe the three ray tracing steps used to identify an image for the given situation.

The buildup of charges on an object is called