A reverse curve consists of :
- Atwo circular arcs of different radii with their centres of curvature on the same side of the different tangents only.
- Btwo circular arcs of same radius with their centres of curvature on the same side of the common tangent only.
- Ctwo circular arcs of different radii with their centres of curvature on the opposite side of the different tangents only.
- Dtwo circular arcs of same or different radii with their centres of curvature on the opposite side of the common tangent.Correct
Solution
Concept
Definition of a reverse (S) curve
Step-by-step solution
1. A reverse curve joins two arcs bending in opposite directions (S-shaped). 2. The two arcs meet at a point of reverse curvature with a common tangent. 3. Their centres lie on opposite sides of the common tangent, and the radii may be equal or different.
Explanation
A reverse curve has two arcs with a common tangent at their junction, curving in opposite senses. A compound curve is the one with centres on the same side.
Why the other options are wrong
Statements (a) and (b) with centres on the same side describe a compound curve. (c) says "different tangents only" and "different radii only", which is not the definition.
Shortcut
Reverse = S shape; compound = same side.
Common mistake
Mixing with the compound curve.
Correct answer: D) two circular arcs of same or different radii with their centres of curvature on the opposite side of the common tangent.