Why does the back of the wing on a commercial airliner extend out during landing procedures? What effect does it have on the aircraft?

Question

Why does the back of the wing on a commercial airliner extend out during landing procedures? What effect does it have on the aircraft?

In: Engineering

Answer 1

Sometimes planes also have them at the front of the wing for the same purpose (of increasing wing surface area). If they are in the front they are called slats