You are on a train moving east at 100 meters/second. You run down the aisle at 10 meters/second. If you are running in the same direction as the train (east), what is your speed with respect to the ground?

I'm pretty sure your speed relative to the ground would be 110 meters per second. However that is just a guess and I'm not 100% sure.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .