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Question
In a two dimensional motion, instantaneous speed v0 is a positive constant. Then which of the following are necessarily true?
Options
The average velocity is not zero at any time.
Average acceleration must always vanish.
Displacements in equal time intervals are equal.
Equal path lengths are traversed in equal intervals.
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Solution
Equal path lengths are traversed in equal intervals.
Explanation:
Speed (Instantaneous Speed): The magnitude of the velocity at any instant of time is known as instantaneous speed or simply speed at that instant of time. It is denoted by v.
Quantitatively: Speed = Distance/Time
Mathematically, it is the time rate at which distance is being travelled by the particle.
- Speed is a scalar quantity. It can never be negative (as shown by the speedometer of our vehicle).
- Instantaneous speed is the speed of a particle at a particular instant of time.
Hence, Total distance travelled = Path length = (Speed) × Time taken
Important point: We should be very careful with the fact that speed is related to the total distance covered not displacement.
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