As we saw in Chapter 1, Newton’s laws are valid only for observers at rest in an inertial frame of reference. But to an observer in a non-inertial frame, like an accelerating car or a rotating carnival ride, the same object will generally move in accelerated curved paths even when no forces act upon it. How then can we do mechanics from the vantage point of actual, non-inertial frames? In many tabletop situations, the effects of the non-inertial perspective are small and can be neglected. Yet even in these situations we often still need to quantify how small these effects are. Furthermore, learning how to study dynamics from the non-inertial vantage point turns out to be critical in understanding many other interesting phenomena, including the directions of large-scale ocean currents, the formation of weather patterns -- including hurricanes and tornados, life inside rotating space colonies or accelerating spacecraft, and rendezvousing with orbiting space stations. There is an infinity of ways a frame might accelerate relative to an inertial frame. Two stand out as particularly interesting and useful: linearly uniformly accelerating frames, and rotating frames.