X b) ABCD is a square of side v2 m. A charge of 2x 10-9C is placed at corner 'A'. Another charge -1x 10-9 C is placed at the centre 'O' of the
square. Calculate the work done in carrying a charge of 2 Coulomb
from corner 'C' to corner 'B'.​

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?