Question

what constant force , tangential to the equator should be applied to the Earth to stop it's rotation​

Answer 1

Answer:

the force required to stop earths rotation is nearly 1000km/hr

Answer 2

Explanation:

Another factor is the earth's "moment of inertia", a concept like mass but related to rotations rather than linear motion. Try this: spin round on a swivel chair, then spread out your arms and you will notice that your rotation slows. Bring your arms in and the rotation will speed up again. With your arms outspread, you have more mass at a distance from your axis of rotation, so your moment of intertia increases. Now angular momentum = moment of intertia x speed of rotation, but this quantity is conserved (if we ignore the friction that eventually stops the chair spinning), so your speed of rotation must drop. If the earth became more oblique or if geological events redistributed its dense iron core to shallower depths, then the earth would rotate more slowly.