Question

if i were to put 40 gears together (spinning anticlockwise) which way would the middle one spin

Answer 1

if the first one rotates anticlockwise, then it will cause a clockwise rotation on the next one, so on and so forth. since there are 40 gears, the middle one, say, the 21st((n/2)+1) one should rotate anticlockwise.

Answer 2

It is about sun and the planetary gear system.All the 4o gears are meshed into the sun( the centre gear) and when the sun rotates clockwise only then other 40 will rotate anticlockwise.