Question

assuming that Earth's radius is 6400 km, find the linear velocity of Quito, Equador, a city on the equator. (Use pi=3.1416 and 1.6 km=1 mile).

Answer 1

I guess we are to do miles per hour ?

v = omega * r
omega = 2 pi /24 hr
r = 6.4*10^3 km (1 mile/1.6 km) = 4,000 miles
so
v = 4000 miles (2 pi/ 24 hr)
=3333 miles/ hour

Answer 2

(2 pi * 6400 km)/(24 hours)

That will give you the answer in km/h. Divide by 1.6 for miles per hour.

Actually, a better conversion factor with five significant figures is 1.6093 km/mile

It makes no sense to have five significant figures for pi and only two for the km-to-miles factor

Answer 3

my choices are
2094.4 mph
209.4 mph
1047.2 mph
104.7 mph

Answer 4

LOL - the textbook writer is using a calculator with pi on it but not the unit conversions :)

Answer 5

v = 4000 miles (2 pi/ 24 hr)
=1047.2 miles/ hour

Answer 6

thnks