where does the serve have to land in tennis
Serve (tennis) For any serve, the server stands behind the baseline without touching it. For the first point of any game, the server stands to the right of the center point of the baseline and serves diagonally across the net to the left side (from the server's perspective) of the court, into the service box which extends to the service line about midway into the opponent's court. For the second point of the game, the serve is diagonally from the left to the right side of the court, and for each subsequent point of the same game the positioning is the opposite of that on the previous point.
Fastest recorded tennis serves Although the Association of Tennis Professionals does not formally recognise service speed records made in Challenger events due to the variance in radar guns, the serve of 263.4 km/h (163.7 mph) recorded by Australian Sam Groth at an ATP Challenger event in Busan, South Korea in May 2012 was measured using approved equipment, and other data gathered appeared within a normal range. However, John Isner holds the official record for the fastest serve at 253 km/h (157.2 mph).[2]