Are the magnitude and direction of `(barA - barB)` same as that of `(barB- barA)`?

What are the magnitude and direction of the electric field at the centre of square in figure if q=1xx10^4 C and a = 5cm.

Ten one-rupee coins are put on top of each other on a table. Each coin has a mass m. Give the magnitude and direction of (a) the force on the 7th coin (counted from the bottom) due to all the coins on its top,(b) the force on the 7th coin by the eighth coin, (c) the reaction of the 6th coin on the 7th coin.

Give the magnitude and direction of the net force acting onfa) a drop of rain falling down with a constant speed. (b) a cork of mass 10 g floating on water. (c) a kite skillfully held stationary in the sky. (cf) a car moving with a constant velocity of 30 km/h on a rough road.

A helicopter of mass 1000 kg rises with a vertical acceleration of 15 m s^2. The crew and the passengers weigh 300 kg. Give the magnitude and direction of the (a) force on the floor by the crew and passengers, (b) action of the rotor of the helicopter on the surrounding air, (c) force on the helicopter due to the surrounding air.

Give -the magnitude and direction of the net force acting on a drop of rain falling down with a constant speed

Give -the magnitude and direction of the net force acting on a cork of mass 10 g floating on water,