A stone falls from rest from the top of a cliff. A second stone is thrown downward from the same height 2.1 s later with an initial speed of41.16 m/s. They hit the ground at the sametime. How long does it take the first stone to hit the ground? The acceleration of gravity is 9.8 m/s2.Answer in units of s.

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.

Can a molecule have bond dipoles but not have a molecular dipole?

The law of entropy can also be called the law of increasing disorder, but this law seems to contradict the existence of living organisms that are able to organize chemicals into organic molecules. prepare for a class debate on the validity of the following arguments: a. living things are not subject to the laws of thermodynamics. b. the increase in the universe's entropy due to life processes is greater than the decrease in entropy within a living organism.