Assertion: An object may have varying speed without having varying velocity. Reason: If the velocity is zero at an instant, the acceleration may not be zero at that instant.

Step-by-step solution

- Assertion is false: An object can have varying speed without having varying velocity (e.g., in uniform circular motion, speed is constant but velocity direction changes, thus velocity varies). Also, an object can have varying velocity without varying speed (e.g., constant speed with changing direction). The assertion states the opposite. - Reason is true: When a ball is thrown upwards, its velocity is instantaneously zero at the peak of its trajectory, but the acceleration due to gravity is still acting downwards