The diagram describes the distribution or circulation of winds. They go from sites of high pressure (H) to sites of low pressure (L).
The terms cold and warm front refers to winds fronts of low or high temperature. When a cold front reaches a warm one, resulting in an occlusion (occluted front).
A strong wind front can be acompanied by clouds (strong winds very cloudy) or not (strong winds cloudless).
Because they both have the same push of gravity. Gravity affects all objects equally. If you drop an egg and a watermelon at the same time they would both collide with the floor at the same time.