Final answer:
The time it takes for the sonic boom of a jet flying at Mach 2 to reach the ground can be calculated using the speed of the jet (680 m/s) and the speed of the sound in conjunction with the altitude of the jet.
Step-by-step explanation:
The student's question relates to the behavior of aircraft when flying at speeds that are expressed in terms of Mach numbers, which corresponds to the ratio of the speed of the aircraft to the speed of sound. When a jet is flying at an altitude of 8.50 km with a speed of Mach 2.00, and the speed of sound is 340 m/s, we can calculate the time it takes for the sonic boom to reach a stationary observer on the ground by using the Mach number formula and the properties of triangles.
The speed of the jet is twice the speed of sound, so it is traveling at 680 m/s (Mach 2.00 times 340 m/s). If the jet is directly overhead, the distance that sound has to travel to reach the observer can be calculated using the Pythagorean theorem, considering the given altitude of the plane and the ground as a right-angled triangle. Finally, dividing the distance by the speed of sound gives the time it would take for the sonic boom to reach the observer.
As for the maximum speeds during the 1970s oil crisis in the United States, which were set at about 90 km/h (55 mi/h), this was done to maintain fuel efficiency in vehicles and reduce consumption due to the drag coefficient's effect on a car's power at highway speeds.