In general terms, it is in whatever direction you're facing.
I expect you ask because of the requirement that the ball is kicked forward on a kick-off. The definition on a kick-off is "more towards the opponent's goal line than your own."
The ball must move forward on the initial kick. Forward is "towards the opponent's goal line."
The ball is in play when it is kicked and moves. The movement does not have to be forward.
No, rugby doesn't have a wide receiver; that's more an American football term and in that game the ball can be thrown forward or kicked forward. In rugby (both codes), the ball can be kicked forward and passed laterally or behind the ball carrier only
it has to be kicked forward
This would not be possible because the moon has less gravity than earth does and it would just float up.
It means the ball was hit (kicked) hard and straight forward.
Forward
The ball must be passed either in line with the ball carrier OR as is normally seen to the rear of the ball carrier. A ball thrown forward, dropped forward of the carrier or knocked forward of the ball carrier is a penalty offense
when a soccer ball is kicked, there is a transfer of energy from your leg to the ball. since the ball is elastic, it coverts the kinetic energy from your leg into potential elastic energy in the for of deformation of the ball. the ball then snaps back to its elastic equilibrium converting the energy back to kinetic energy. also, your momentum is being transferred to the ball, giving it a direction since momentum is a vector. due to these conversions of energy and momentum, the ball is sent off your foot in the direction you kicked it with the same speed you kicked it with.
Knowing the trajectory of the ball as it is kicked upwards. Noticing it's change in direction with each little touch and yes, practise.
A soccer ball is mostly kicked or sometimes football or flag football
The answer depends on the direction (upward, horizontal, or downward) in which the ball leaves his foot.
Primarily the direction of movement, the spin on the ball and the movement of the surrounding air (wind). The effect is called the "Magnus Effect" (google that to get more details).