What is the maximum angle F-16 can turn in x seconds flying at corner speed?
To calculate this, you need to look at the energy Maneuver diagram for the aircraft. This diagram depicts, for a specified altitude and gross weight, the excess power per unit pound of weight the aircraft would have at full afterburner at any g-Loading and true airspeed. There would be a different chart for each aircraft configuration, gross weight and Density Altitude combination. 

Instantaneous Turn rate is depicted on the vertical scale, true airspeed or mach number is depicted on the horizontal scale. The concave curved lines that go from upper left to far right represent flight conditions of constant G-loading, while the straight lines that radiate from the origin represent constant turn radius. The peak of the flight envelope, (at about Mach 0.7, 20 deg/sec turn rate and 8 Gs, is corner velocity. The lines that start at the left boundary or at the bottom, go upwards, curve to the right and then back down again, and are labeled with values 600, 400, 300, 0, -200, etc. are called Ps, (pronounced P-sub-S), lines. They depict the specific power, or actually, specific excess power - a measure of how much power per pound of aircraft weight the aircraft would have left over to climb or accelerate at the depicted point on the diagram. 
So at the top of the diagram, at the corner velocity, where the turn rate is near 20 deg/sec, the specific excess power is less than -800. The -800+ Ps curve indicates that the aircraft, if it established flight at those conditions, would be bleeding energy (airspeed or altitude) at a rate in excess of negative 800 ft/sec. 

The best performance on the diagram that can be sustained, on the other hand, is the highest point on the zero Ps line, which is at mach 0.8, 7 Gs, and it would produce a sustained turn rate of just over 14 deg/sec. 

So, in a level turn, at Mach 0.8, 7 Gs, and 14 deg/sec, the F-16 could turn 180 degrees in about 13 secs.

Of course, if the aircraft performs the turn in a descent, it can make the turn in less time. This is indeed a common training maneuver, to turn 180 degrees in the shortest amount of time possible. It is performed by rolling into 135 degrees of bank at or slightly above corner velocity and pulling at maximum G-load. The maneuver is performed at maximum available G-load, in a constant plane tilted at 45 degrees from the horizontal. Bank angle (starting at 135 degrees), decreases throughout the maneuver, reaching 90 degrees bank after 90 degrees of turn, and 45 degrees bank at the end of the maneuver (after 180 degrees of turn). At 15,000 feet MSL, this will generate almost 20 degrees per second, and can be done in about 10 seconds.