Atrain has a constant speed of 10 m/s around a track with a diameter of 45 m what is the centripal acceleration?

Explanation:

When an object goes on a circular movement, it has a centripetal acceleration that always points toward the center of the circle, it is the responsible of the change of direction in the movement of the object. and that centripetal acceleration is related with the speed in the next way:

, with v the speed, r the radius of the track that is half of the diameter (22.5 m)

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 .