Why does the coil of wire spin when current is applied to the armature? why does the magnet not move?

Here the right answer 

The motor is connected to a battery. When the switch is closed, the current starts to flow and the coil becomes an electromagnet. In this case the current is flowing anticlockwise in the top of the coil. This makes the top a north pole. This north pole is attracted to the south pole on the left. So the top of the coil turns towards the left. Notice that the bottom of the coil is a south pole and is attracted to the magnet on the right. Hope this helped

Iwould choose the same momentum because if they throw a baseball very light and not hard at all then doing it with a bowling ball won’t hurt that worse