Question

Two students are arguing over the differences between speed and velocity. One student says,

“Speed is a scalar because it describes how fast an object is traveling. Velocity is a vector because it tells how fast and in what direction an object is traveling.” Which of the following statements is correct? (AKS 1b3 DOK 3)

Question 3 options:

The student’s understanding of all four terms (speed, velocity, scalar, and vector) is correct.


The student’s understanding of speed and velocity is correct but their understanding of scalar and vector is incorrect.


The student’s understanding of all four terms (speed, velocity, scalar, and vector) is incorrect.


The student’s understanding of speed and velocity is incorrect but their understanding of scalar and vector is correct.

Answer 1

Answer: The student’s understanding of all four terms (speed, velocity, scalar, and vector) is correct.

Step-by-step explanation:

Let's start by explaining that a vector is one that has a numerical value along with its units (called a module) and a direction, while a scalar is only determined with a number and its corresponding units, without direction.

Then, speed is the distance an object travels in a given time. That is, it only takes into account the distance traveled, dividing it by time to know how fast it moves, therefore it is a scalar.

Instead, velocity refers to the time it takes for an object to move in a certain direction. So, by involving the direction of movement, velocity is a vector.

In short, the speed does not take into account the direction of the object, while the velocity does.

Therefore, as the student understands this four concepts, the correct option is:

The student’s understanding of all four terms (speed, velocity, scalar, and vector) is correct.