Question

A particle moves along a semicircle of radius 10m in 5 seconds. What is the average velocity of the particle?

Answer 1

Task. A particle moves along a semicircle of radius 10m in 5 seconds. What is the average velocity of the particle?

Solution. The length of the circle of radius $r$ is equal to

$l=2\pi r.$

By assumption, during $t=5$ sec. the particle passed a semicircle of radius $r=10$ m, so the length of this part is equal to

$d=l/2=\frac{2\pi r}{2}=\pi r.$

Therefore the average velocity is equal to

$v=\frac{d}{t}=\frac{\pi r}{t}=\frac{3.14*10}{5}=6.18m/s.$

Answer. $6.18m/s.$