Step-by-step explanation:
very simple thought experiment :
he is going 90 km/h (90 kilometers per hour), so, he moving 90 km in 1 hour.
how far is he going in just 2 seconds ?
so, we get two ratios.
90km/1 hour = 90,000 meter / 1 hour
x meter / 2 seconds
we need to bring both ratios (they are fractions) to the same dimension of the denominators, so that we can then bring them to the same denominator.
the first is dealing with an hour.
the second one with (2) seconds.
so, how many seconds are in 1 hour ?
60 seconds per minute, 60 minutes in the hour.
60×60 = 3600 seconds.
so, now we know, the first ratio is also
90,000 meter / 3600 seconds
now we need the factor to to multiply numerator and denominator with to bring 3600 down to 2.
3600 × f = 2
f = 2/3600 = 1/1800
now we get
90,000 / 3600 × (1/1800) / (1/1800) =
(90000 / 1800) / (3600 / 1800) = 50 / 2
so, 90km/h is the same speed as 50 meter / 2 seconds.
and therefore we know, the building was 50 meters long.
