what is acceleration can i able to feel that?

Answer 1

Displacement is where you are relative to a reference point. (eg I am 2 metres away from that tree.)
Velocity is the rate of change of displacement. (eg I am moving towards the tree at 2 metres per second)
Acceleration is the rate of change of velocity. (eg I was moving at 2 metres per second, now I am going faster at 3 metres per second)

Acceleration is the only one of the above three you should be able to feel - this is because the fluid in your middle ear, which regulates your balance, doesn't go as fast as the rest of you. This is why when you speed up you get the sensation that you're falling backwards, even if your posture hasn't changed.

You will also feel it when you hit the tree.