An airplane travels 3100 km at a speed of 790 km/h, and then encounters a tailwind that boosts its speed to 990 km/h for the next 2800 km. What was the avg. speed of the plane for this trip?
2007-08-28 15:13:31 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Stage 1:
3100 km / 790 km/h = 3.92 h
Stage 2:
2800 km / 990 km/h = 2.83 h
Total average speed:
(3100 km + 2800 km) / (3.92 h + 2.83 h) =
5900 km / 6.75 h = 874.07 km/h
2007-08-28 15:48:00 · answer #1 · answered by skeptik 7 · 0⤊ 0⤋
Average speed is Total distance / total time.
V = [3100 + 2800] / total time.
Total time = 3100 / 790 +2800 /990.
Since time = distance / speed
Total time = 6.75 hour
V = [3100 + 2800] / 6.75 = 874 km/h
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2007-08-28 22:45:55 · answer #2 · answered by Pearlsawme 7 · 0⤊ 0⤋
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2007-08-28 23:05:52 · answer #3 · answered by Anonymous · 0⤊ 0⤋