Question

A skater glides along circular path of radius 5.00 m. If he coasts around one half of the circle, find magnitude of displacement vector and how far the person skated and what is the magnitude of displacement if he skates all the way around the circle?

Answer 1

The magnitude of displacement vector is just the diameter because it is the difference between the final and initial position: $D=2r=2·5=10\text{ m}.$

How far the person skated in the half of circle:

$$L=\pi r=15.7\text{ m}.$$

If he skates all way round the circle and makes one complete loop, the displacement is zero because the final and initial position are the same.