Astudent thinks that the more protons an atom has, the more reactive it will be. which will best disprove this student's idea?

compare the reactivities of lithium (li) and krypton (kr).
note that rubidium has 48 neutrons.
compare the number of protons in cesium (ce) and xenon (xe).
count the number of neutrons in an atom of helium.

Abird sitting high in a tree is an example of what type of wnergy

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.