Question

A scientist uses a submarine to study ocean life. She begins at sea level, which is at an elevation of 0 feet She travels straight down for 90 seconds at a speed of 3.5 feet per second. She then travels directly up for 30 seconds at a speed of 2.2 feet per second. After this 120-second period, how much time, in seconds, will it take for the scientist to travel back to sea level at the submarine’s maximum speed of 4.8 feet per second? Round your answer to the nearest tenth of a second.

Answer 1

Distance = speed*time
 1st              = 90*3.5
               = 315ft
2nd         = 30*2.2
               = 66ft
0-315+66= -315+66= -249ft
(249/4.8)= 51.875 = 51.86 seconds
Hope this helps.