"Rotational speed" refers to how fast something is spinning or rotating. It measures the speed at which an object, like a wheel or a fan, turns around its center or axis. Full definition
It also allows a difference in rotational speed of the impeller and turbine - convertor slip. (mechanics.stackexchange.com)
Where winds are blowing east, that motion adds speed to the planet's already high rotational speed of about 43,000 kilometers per hour (27,000 miles per hour). (seeker.com)
Answer: The brake systems use sensors near each wheel that monitor rotational speed to determine when the wheels are about to lose traction and lock up. (articles.orlandosentinel.com)