What is going to happen to the earth if the core stoped spinning?

Slowing and reversing is a natural part of the core's cycle. However, if our Earth's core cools, the magnetic field will disappear and the planet will become similar to Mars. If the Earth itself stops spinning it would be bad. At the Equator, the earth's rotational motion is at its fastest, about a thousand miles an hour. If that motion suddenly stopped, the momentum would send things flying eastward. Moving rocks and oceans would trigger earthquakes and tsunamis. The still-moving atmosphere would scour landscapes.