Suppose a log's mass is 5 kg. after burning, the mass of the ash is 1 kg. explain what may have happened to the other 4 kg

Can somebody explain to me how newton's 3rd law relates to momentum? ~ap physics 1

An electron is traveling with initial kinetic energy k in a uniform electric field. the electron comes to rest momentarily after traveling a distance d. (a) what is the magnitude of the electric field

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e