Uma criança anda em uma pista circular de raio 100m, gastando 20 minutos para percorrer metade da pista. Indique o deslocamento da criança.

200m

Explanation:

This can be translated to:

A child walks on a circular track with a radius of 100m, spending 20 minutes to cover half the track. Indicate the child's displacement.

Ok, we want to know the displacement, which is equal to the difference between the initial position and the final position.

if the kid starts at any point of the circular track, we know that he covers half the track, so he actually covers a semicircle.

This means that we can connect the initial position and the final position with the diameter of the circle.

(The diameter is two times the radius).

Then the distance between the final position and the initial position (the total displacement) is equal to two times the radius:

Displacement = 2*100m = 200m

answer: decibel

explanation: