A parallel plate capacitor has two plates of area A separated by a small distance d. The capacitor is charged to a potential difference of V and the b

A parallel plate capacitor has two plates of area A separated by a small distance d. The capacitor is charged to a potential difference of V and the battery is disconnected. A metal plate with area A and thickness `(d)/(2)` is fully inserted between the plates, so that it always remains parallel to the plates.
(a) Calculate the work done on the metal slab while it was inserted.
(b) Does the two plates of the capacitor attract of repel the metal plate that is being inserted. Does the answer obtained in part (a) help you in answering this ?