Two objects traveling at the same speed have different velocities if they

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

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value

You can decrease the resistance of a length of wire by