Those lines are baselines, if you are referring to the boundary lines on both sides of the tennis court which run parallel to and are at the greatest distance away from the net.
The farest line from the net parralell from the net. The server stands behind it.
The tennis service line is located 21 feet from the net on a tennis court.
it is the first horizontal line from the net.
The service line on a tennis court is located parallel to the net, dividing the court in half. It is 21 feet from the net in singles matches and 27 feet from the net in doubles matches.
It is the third law of motion because it has to do with action reaction things. Tennis ball hitting the net is the action, and it falling to the ground is the reaction. I hope this helped.
a tennis net
Tennis court lines are referred to as the "baseline", "service line", "singles line", "doubles line", and "center line". There is also a small "center mark" protruding from the court in the middle of each baseline.
The net should be 3' (36") or 91.5cm at the center strap, and 3'6" (42") or 106.5cm at the post. You can stand your racquet on the ground for reference.
The answer is 31, assuming the net counts as a line.
The middle of a tennis net (lawn or otherwise) is held in place at exactly 36" from the ground by the "center strap". The measurement is checked by a tennis official (or by a player, if there is no official, as is the case for most social settings), and the strap is adjusted, as needed. Refer to the USTA link, below, for further information about tennis nets.
The standard tennis net is three feet high, exactly one yard.
Two or four people flinging a ball across a court that is divided by a ground net with netted raquets.