Where's the physics?
From this scene, we can determine that Kevin demonstrates projectile motion when he launches himself into the air at a certain degree in order to cannonball effectively into the pool. We can assume the angle of his jump being 50 degrees and the length of his jump as 2 metres, with the jump lasting 1 second long.  With this information we can find the depth of the pool he jumps into in metres. 

Finding the depth of the pool: 
x stuff:
△dx = 2m
vx = 1Cos50 = 0.64m/s
t = 1s

y stuff:
vy1 = 1Sin50 = 0.77m/s
a = -9.8 m/s^2
t = 1s
 

The swimming pool scene was shot at the Four Seasons in Chicago, Illinois, because the Plaza Hotel doesn't have a swimming pool located on-site. The renovated house where Kevin sets up his traps is not actually in New York City.