Vehicles carrying inflammable materials usually have metallic ropes touching the ground during the motion. why?

vehicles carrying inflammable materials usually have metallic ropes touching the ground during the motion of the vehicle because the body of the vehicle in motion is charged due to air friction.

explanation:

friction causes the vehicle to become charged and can pose a threat. so excess static and friction is let off on the ground by the ropes

dec 23, 2016 - a load of bricks weighing 680 n a distance of 10 m across a parking lot. if if the worker pushes the cart with a constant force of 209 n, what work= force x distance = 220 n x 10 m = 2200 n.m = 2200 j i don't know where the person got it from, but the initial part, work= force x distance me.