A turtle takes 3.5 minutes to walk 18m toward the south along a deserted highway. A truck driver stops and picks up the turtle. The driver takes the turtle to a town 1.1km to the north with an average speed of 12m/s. What is the magnitude of the average velocity of the turtle for its entire journey?
Please could you explain each step (and the reason for it)? Many thanks.
First of all we have to find the total displacement of the turtle.
Please refer to the attached image.
Let initial position of the turtle be P. The turtle has moved 18m south when picked up by the truck driver at point Q. From Q the truck driver takes the turtle 1.1km=1100m north to point R.
Hence, the shortest distance between the initial and final position of the turtle or displacement is given by PR i.e QR-PQ=(1100-18)=1082m north.
Time taken by the turtle to travel= 3.5 mins = 210 secs.
Average speed of the truck driver=12m/s
So, the truck driver spent (1100/12) = 91.667 secs. carrying the turtle.
Total time = (210+91.667)secs=301.667 secs
Average velocity=Total displacement/Total time taken
=1,082/301.667`~~` 3.587m/sec., north
Therefore, the magnitude of the average velocity of the turtle for its entire journey is 3.587 m/sec.