Problem: How long does it take an object moving at 5 meters/second to move 4.5 meters?
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Solution: At 5 meters every second, it will clearly take less than a second to move 4.5 meters. The ratio of distance moved to distance in a second is 4.5 / 5, so the time interval is 4.5 / 5 seconds = .9000 second.
Generalized Response: We can obviously rearrange
`dist = v `dt
into the form
`dt = `dist / v.
This form represents the ratio `dist / v of the distance moved to the distance moved in a second.
If, as in the present problem, the numerical value of `dist is less than that of v, this means that we have moved less distance than would be moved in a second. So the time interval `dt is less than a second.
The smaller the ratio `dist / v, the less the time required.
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Figure description:
We can reason out the result, as above. As an alternative, the figure below shows the diagram in the form of a 'relationship triangle' between `ds, `dt and vAve, showing how we can use the known quantities `ds and vAve to find the time interval `dt.
