A charge particle 'q' is shot towards another charged particle 'Q' which is fixed , with a speed 'v'.It approaches 'Q' upto a closest distance r and then returns . If q were given a speed of '2v' the closest distance of approach would be
(a)r2(b)2r(c)r(d)r4

Achemistry student needs of 40ml diethylamine for an experiment. by consulting the crc handbook of chemistry and physics, the student discovers that the density of diethylamine is 0.7 . calculate the mass of diethylamine the student should weigh out. round your answer to significant digits.

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !

Me with this and you will be marked brainliest