Q: The place where a river meets the sea is called a(n) __________. A. estuary B. isthmus C. escarpment D. peninsula. A: Place where river meets sea is estuary. Log in to see link for more information.
Although The Guinness Book of Records recorded the XF-84H as the fastest propeller-driven aircraft ever built, with a design top speed of 670 mph (1,080 km/h) (Mach 0.9) and 623 mph (1,003 km/h) (Mach 0.83) during tests, this claim has been disputed.
Although the official record is about Mach 3.3 (or 3.3 times the speed of sound), many believe the aircraft could actually fly much faster. However, it seems unlikely that the SR-71 could go much faster than about Mach 3.5, with a very slim chance of Mach 4, due to propulsion and structural limitations.