Question

Find the speed at which earth rotates on its axis (radius of the earth=6400 km)

Answer 1

$omega \: = 2\pi \div time \: period$
Therefore, speed = 2*3.14 /86400
=6.28/86400
=7.2

Answer 2

speed :- The distance covered by an object with respect to time is called speed.
(the rate of change in distance of an object).

1 day = 60×60×24 second = 86400second
time taken by earth to revolve on it's orbit = 86400s

earth revolve on it's orbit in circular motion so
distance = 2πr = 2×π×6400 km = 40212.386km

speed = distance/time
speed = 40212.386/86400
speed = 0.465km/s
speed = 0.465 × 10³m/s
speed = 465m/s