if it is concave then the light is reflected at one direction.
if it is convex the light is reflected outwards and they will travel away from the focal point and the light scatters or will be reflected to different directions
We don't know that at all. The 3rd law says that the REaction is opposite and EQUAL to the action. We don't know where that "twice as much" comes from.
Eneregy is the ability to to do work
it takes work to heat someone
heat is energy
put the solid metal block in a campfire and heat it up
tada
wait, we need the options, nevermind
