6. a killer whale can swim as fast as 15 m/s. suppose a killer whale swims in
one direction at this speed for 8.0 s, makes a 90° turn, and continues
swimming in the new direction with the same speed as before. after a certain
time interval, the magnitude of the resultant displacement is 180.0 m.
calculate the amount of time the whale swims after changing direction.

if possible i could use a step by step answer

8.9 s

Explanation:

First, the killer whale swims at 15 m/s for 8.0 s.  The distance is:

15 m/s × 8.0 s = 120 m

Then, the killer whale turns 90° and swims at 15 m/s for t seconds.  The distance is:

15 m/s × t s = 15t m

These two distances form the legs of a right triangle.  The resultant displacement is the hypotenuse.  So using Pythagorean theorem:

(180)² = (120)² + (15t)²

32400 = 14400 + 225t²

18000 = 225t²

t² = 80

t = 8.9

The whale swims for 8.9 seconds after turning.

d is the correct answer

it is called kinetic energy