Question

A rescue helicopter is used to help victims who fell in a ditch. The helicopter begins at sea level, which is an elevation of 0 feet. It then travels down for 100 seconds at a speed of 10.5 feet per second. It then travels directly up for 150 seconds at a speed of 5.2 feet per second. After this 250 second period, how much time, in seconds, will it take for the rescue helicopter to travel back to sea level at the helicopter's maximum speed of 15.8 feet per second?

Answer 1

Answer is 17.088 seconds

Explanation:

We have given,

Speed of helicopter while going down = 10.5feet/sec

Time taken to travel down = 100 sec

Distance covered while going down = speed * time

Distance covered while going down = 10.5 * 100

Distance covered while going down = 1050 feet

Now,

Speed of helicopter while going up = 5.2feet/sec

time taken to travel up = 150 sec

Distance covered while going up = 5.2 * 150 = 780 feet

After this 250 second period , the position of helicopter will be:

Position of helicopter = distance covered in downward - distance covered upward

Position of helicopter = 1050 - 780 = 270 feet

That means we need to travel upward a distance of 270 feet at a maximum speed of 15.8feet/sec to reach sea level.

Time taken to reach sea level = distance/ speed = 270/15.8 = 17.088 sec

Hence time taken to reach at sea level with maximum speed is 17.088 seconds.