It's mechanicaly operated hydraulic. You do realize that no matter how horrible brakes are on a car you could lock them up on anything. And yes even how much force you put on the pedal is going to affect the pressure you'll have pushing against your caliper piston. Why do you think they put a brake booster and a lever with a ratio of like 10-1 for your brake pedal. Have you ever tried to stop your car without your power brakes you'll see what I mean about the force of your leg.