Please explain instantaneous velocity and the expression dx/dt.

Asked by krishnan iyer | 15th Aug, 2010, 02:37: PM

Expert Answer:

Velocity is net displacement/time i.e. final position - initial position / change in time = Δx/Δt.
Now Δ signifies the change in quantity by final value less the initial value. But to know the change in quantity instantanesous, we need to capture an instant. Instant i.e. very very short interval of time, as small as we think it's zero, since it may be 0.0000000001 sec or 0.0000000000001 sec. We just choose to singal it by saying Δt tends to zero, and by doing this we can't just use the Δ now, so we replace it by d, and say dx/dt, signalling it's differential change. Instantaneous velocity is the velocity that we know instantly, and are no longer talking about velocity at 1 min or after 1 hr.

Answered by  | 15th Aug, 2010, 02:53: PM

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