Question

If an object starts at rest and moves 60 meters north along a straight line in 2 seconds, what is the average velocity?

Answer 1

Velocity: 30 m/s north

Answer 2

Answer:

The average velocity, expressed as a vector, is v=30 m/s with direction north.

Explanation:

In this case, we will obtain a vector velocity, and the correct answer will be expressed as a vector. But as the movement happens only along a straight line (with direction to the north from the point of rest), we can do the math calculation as a one-dimensional problem. Then the final velocity will be a vector with the calculated magnitude, pointing to the north, as we already know.

The question is simple, as we were given the distance in meters that the object moved in a straight line, and the time in seconds that took the object to move that distance, we have the correct units and we can write the average velocity as

$v=\frac{d}{t}$

where d is the distance, and t is the time. Therefore

$v=\frac{60m}{2s}=30\frac{m}{s}$

which is the magnitude of the velocity we wanted to know, then we express it as vector saying its direction (north, for our system of reference).