A runner runs around a track consisting of two parallel lines 96 m long connected at the ends by two semicircles with a radius of 49 m. She completes one lap in 100 seconds. What is her average velocity?

Answers:0m/s

Step-by-step explanation: once she has completed one lap, displacement is 0, therefore her velocity is 0m/s

5 m/s

Step-by-step explanation:

First task is to find the total length of the track.

We know it's made out of 2 straight lines of 96 m long ... and 2 semicircles with a radius of 49 m.

Since we have TWO semicircles, we can say we have one circle ... so we can calculate its circumference:

C = 2 * π * r = 2 * 3.14 * 49 = 307.72 m

This is for the both semicircles at the ends. Now, let's add the two 96 m long straight lines to get the full length of the track:

T = 307.72 + 96 + 96 = 499.72 m

Now that we have the total length of the track, we can easily calculate her average speed.

She does one lap in 100 seconds, so her average speed/velocity is:

S = 499.72 m / 100 s = 4.9972 m/s or 5 m/s if we round up a bit.