Question

How fast does Earth rotate near the equator?

Answer 1

Hint: As a first step, you could recall the time period of rotation of our planet earth. Then you could simply recall the definition of velocity, from which you will get the expression for the same. Now you could simply substitute this value of time period and take the circumference for the distance to get the velocity.
Formula used:
Velocity,
$v=\dfrac{x}{t}$

Complete answer:
In the question, we are asked how fast the Earth rotates near the equator.
Now let us recall the value of Earth’s circumference at the equator whose approximate value is known to be 40075km. Also, we know that the time period of rotation of earth about its axis is approximately equal to 1 day that is 24 hours. Now, we have the distance as well as time and then we could easily calculate the velocity.
We know that velocity is given by the distance travelled per unit time, that is,
$v=\dfrac{x}{t}$
Now, we could substitute the values accordingly.
$v=\dfrac{40075}{24}$
$\therefore v=1674.44km{{h}^{-1}}$
So, we got the speed of earth spin at the equator as$1674.44km{{h}^{-1}}$.

Additional information:
The direction of rotation of our planet earth is found to be eastward. It is a known fact that over time, the Earth’s rotation is slowing down and thus we could say that days are longer now when compared to the past. This has to do with the tidal effects of the moon and the rotation of our planet.

Note:
The above obtained value of speed earth’s spin can be given in other units. In meters per second, it is found to be 460meters per second and in miles per hour it is about 1000miles per hour. If you are wondering about the origin of this rotation, it dates back to the time when the big bang took place.