You just crossed the runway threshold, and the runway's width suddenly fills your windscreen faster than you anticipated. You quickly pull back on the control yoke, feel the airplane stall, and touch down hard the runway.
Carrying extra airspeed on final approach, and flying faster than the manufacturer recommends for your weight, usually makes it more difficult to land.
It's pretty much impossible to explain aerodynamics without heavily simplifying it. Aerodynamics is a field for engineers, based on differential equations that don't have much use in the cockpit.
When you bank while maintaining altitude, your stall speed increases. It's something that you need to be aware of, especially when you're in the traffic pattern. So why does stall speed increase when you start rolling left or right?
Have you ever seen your descent rate exceed 1,000 feet per minute on an instrument approach? Here's why you should take corrective action if it happens.