If you walk at 2 m/s in a perfect circle, what is changing?

choices: a. speed
b. mass
c. volume
d. velocity

d. velocity

Explanation:

First of all, we must identify the difference between speed and velocity:

- Speed is a scalar quantity, defined as the ratio between the distance covered by an object and the time taken. Being a scalar, it does not have a direction.

- Velocity is a vector quantity, defined as the ratio between the displacement of the object (change in position) and the time taken. Being a vector, velocity has both a magnitude and a direction.

Now let's go back to the problem. You are walking at 2 m/s: it means that this value does not change, so your speed is constant.

However, you are walking in a circle. This means that the direction of your motion is constantly changing: therefore, your velocity is changing. So the correct answer is

d. velocity