Based on the official MLB pitching distance of 60' 6" .. it takes .5 seconds for a 100 mph fastball to reach home plate.
However, in reality, if the Baseball is thrown by a person, it actually reaches the plates quicker because most MLB pitchers are 6'+ and there stride towards home plate will have them releasing the baseball closer than 60' 6".
92 miles an hour
Well, that all depends on the pitcher throwing the ball. Some pitchers have been known to throw a ball over 100 miles per hour.
Approximately 1/2 second.
82 miles per hour
Most likely, yes.
In physics, Velocity = Distance/Time. Therefore, Time= Distance/Velocity. Insert the Velocity and you get Time= Distance/100. However you'd have to convert either the distance to miles or velocity to feet. 1 mile= 5,280 feet
2 miles per hour faster
75 miles per hour is about 110 feet per second. So a pitch thrown at that speed will reach home plate in a little more than half a second (about .55 seconds). A pitch thrown at 90 MPH will reach the batter in about a tenth of a second less (.45 seconds).