Help with Ratios

Question

At a playground, a child is watching a merry-go-round and decides to figure out something about how quickly it is rotating. The child measures the number N of seconds it takes the merry-go-round to complete 4 revolutions. Suppose the child then was to calculate the quantity 4 revolutions/Nseconds =4/N rev/s. This could be interpreted as:

a)the time for the merry-go-round to complete 4/N revolutions.

b)The number of revolutions the merry-go-round would complete in 4/N seconds.

c)The number of revolutions the merry-go-round would complete in 1 second.

d)The number of seconds for the merry-go-round to complete 1 revolution.

Answer 1

If N = 60 seconds, then 4/N = 4/60 which reduces to 1/15 rev/sec. So 4/N is the number of revolutions (1/15) completed in 1 sec. In this case it's a fraction. I would go with (c) as the best answer choice, although (a) can be interpreted as meaning the same thing.

Answer 2

A.

The quantity 4�N4​ revolutions per second, where �N represents the number of seconds it takes for the merry-go-round to complete 4 revolutions, can be interpreted as the rotational frequency or angular speed of the merry-go-round.