Explanation: During the night the earth has moved around the sun. It is the illusion that the sun goes up and down. This was in the time before Copernicus. Have we really learnt something since then?

15. 9 cm along the whole Earth!

Explanation:

The cable is 1-meter shot. The circumference of the Earth is 2πR (R= radius of the Earth) 40.000 km

The length of the cable is 2πR - 100 cm. This means that a simple calculation teaches us the following:

2πR : R = 100 cm : X;   X = 100 . R ;     X = 100 ;     X = 100 ;   X = 15.92 cm (Q.E.D)