Plate compactors fall into one of three categories: single plate compactors that move in only a forward direction, reversible which move in forward and reverse, and high performance/heavy-duty plate compactors. The handle of a plate compactor plays a key roll. It can be mounted in the center or back of the unit. It can be a swinging handle allowing for easier maneuverability. And it could also be an anti-vibration hadle for increased operator comfort. Equipment is a key element in paving and pavement maintenance.
When hovering, hummingbirds hold their bodies upright and flap their wings horizontally in a shallow figure-8. As the wings swing back they tilt flat for a moment before the wings are drawn. Most hummingbirds flap their wings about 50 or so times a second.
During a chase, however, speeds increase; ducks, for example, can fly 60 mph or even faster, and it has been reported that a Peregrine Falcon can stoop at speeds of 200 mph (100 mph may be nearer the norm). Interestingly, there is little relationship between the size of a bird and how fast it flies. Both hummingbirds and geese can reach roughly the same maximum speeds. There is, of course, a considerable difference between the speed at which a bird can fly and the speed at which it normally does fly.