It will take 51.9 seconds to return to sea level.
The rate of change of position of an object in any direction. Speed is measured as the ratio of distance to the time in which the distance was covered.
Using the speed - distance relationship, the time taken for the scientist to travel back to sea level would be 51.9 seconds
Distance = Speed × time
First travel :
Distance covered = 90 × 3.5 = 315 feet
Second travel :
Distance covered = 30 × 2.2 = 66 feet
Net change in position from sea level :
(315 - 66) feet = 249 feet
Maximum speed = 4.8 feet per second
Time taken = Distance / speed
Time taken = 249 ÷ 4.8 = 51.875 seconds
Hence, it will take 51.9 seconds to return to sea level.
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