The runner reaches the first camera, at the 500 m mark, at 9:03:05 a. m. and the second camera, at the 600 m mark, at 9:03:25 a. m. What is her average speed over that time interval

Explanation:

Distance travelled = 600 - 500 = 100 m

Time taken = 9:03:25 a.m.-  9:03 :05 a.m.

= 20 s

average speed = distance / time taken

= 100 / 20 m /s

= 5 m /s

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 .