According to information from Wikipedia, the longest escalators in Prague are at Náměstí Míru.
They travel a distance l = 87.1 m in t = 140 s. It is also said that the handrails on the escalators
move δv = 2.0 % faster than the stairs in order to ensure alertness. How much would your arm
move relative to the rest of your body (if it was long enough) during the entire escalator ride,
if you stood on the same stair while holding one spot the whole time?
We expect a number with 3 significant digits in units m as a result