The correct option is (b).
Explanation
Uniform Circular Motion is defined as the motion of an object traveling along a circular path at a constant speed. In this type of motion, while the speed (magnitude of velocity) remains constant, the direction of the velocity vector changes continuously at every point. Consequently, it is considered an accelerated motion due to the change in direction.
- Statement 1 is Incorrect: The motion of a car on a straight road is an example of rectilinear motion (motion along a straight line). It does not involve a circular trajectory.
- Statement 2 is Correct: A cyclist moving on a circular track at a constant speed satisfies the specific criteria for uniform circular motion: the path is circular, and the speed is constant.
- Statement 3 is Incorrect: A train moving on a straight track is another example of rectilinear motion. It lacks the circular path required to be classified as circular motion.
Key Takeaway: The defining characteristics of uniform circular motion are a circular trajectory and a constant speed. Motion along a straight path is distinct and is termed rectilinear motion.