Question

why is a road bank on a circular turn

Answer 1

abhi Tumko yaad aa raha hai aap 50.1 send kar Tum Dena nahi diya aapka. Kaisa chal raha hai

Answer 2

Objects in motion tend to stay in motion (going at the same speed, in the same direction) unless acted upon by an outside force.  So, let's say you're in a car that's travelling at 100mph down a straight road.  If you want to change direction (ie, negotiate a curve), something has to provide the push.  You might think it's your car, but it's actually the road that supplies that force (just think...what happens when you try to turn and hit a patch of ice, or sand? You slide in the same direction you were travelling when you initially hit the patch.  Why? Because there's no friction being provided by the riding surface to keep you on the road).

On a flat surface, friction between the wheels and the road is the only force helping you turn.  But remember, your car still wants to continue in the original direction