Concepts Of Physics MCQ Edition [Volume 1]
- Exam
- Concepts Of Physics MCQ Edition [Volume 1]
- Subject
- Physics
- Chapter
- Rest and Motion Kinematics
Concepts Of Physics MCQ Edition [Volume 1] · Physics · Rest and Motion Kinematics
Identify the correct statements:
Identify the correct statements:
Options
- AThere can be a situation where the speed of a particle is never zero, but its average speed over an interval is zero.
- BThe magnitude of a particle's velocity is equal to its speed.
- CThe magnitude of average velocity over an interval is equal to its average speed during that interval.
- DThere can be a situation where the speed of a particle is always zero, but its average speed is not zero.
Correct answer
B. The magnitude of a particle's velocity is equal to its speed.
Step-by-step solution
Average speed is the ratio of total distance to total time. Since distance is a non-negative scalar, if the speed is never zero, the distance covered is strictly positive, making the average speed non-zero. Hence, the first statement is incorrect.
The magnitude of instantaneous velocity is defined as the instantaneous speed. Hence, the second statement is correct.
Average velocity is the ratio of total displacement to total time. Since the magnitude of displacement is less than or equal to the total distance covered, the magnitude of average velocity is less than or equal to the average speed. They are equal only for unidirectional straight-line motion. Hence, the third statement is incorrect.
If the speed of a particle is always zero, it is at rest, meaning the total distance covered is zero. Therefore, its average speed must be zero. Hence, the fourth statement is incorrect.
The magnitude of instantaneous velocity is defined as the instantaneous speed. Hence, the second statement is correct.
Average velocity is the ratio of total displacement to total time. Since the magnitude of displacement is less than or equal to the total distance covered, the magnitude of average velocity is less than or equal to the average speed. They are equal only for unidirectional straight-line motion. Hence, the third statement is incorrect.
If the speed of a particle is always zero, it is at rest, meaning the total distance covered is zero. Therefore, its average speed must be zero. Hence, the fourth statement is incorrect.