And since I'm in that mood...Zeidmaan, that D40 most likely wouldn't satisfy his needs..
CNET wrote:
Slow kit lens; occasionally slow to focus
Looking past the fact that the camera would most likely not be able to accurately track a guy skating.. the kit lens is "slow". It has a small maximum aperture, thus it doesn't let in that much light..
If I may:
The max aperture of the lens is f/3.5 at 18mm. Back in the days of film, there was a rule called the "Sunny 16 Rule". On a bright sunny day, if you dialed in an aperture of f/16, and set your shutter speed to 1/focal length, your image should be in the ballpark for correct exposure (granted, your film had to be ISO100 speed).
Applying that here:
Effective focal length when the lens is set to 18mm -> ~30mm.. so the shutter speed for correct exposure at f/16 is 1/30. Converting 1/30s @ f/16 to f/3.5, we get a shutter speed of ~1/500.
While that is enough to stop the action, it falls well short of 1/4000th of a second. Also, if it is overcast or not totally bright outside then it will be 1-2 stops less (so from 1/250th to 1/125th).. which isn't fast enough to stop the action.