Can you use speed and velocity interchangeably?

[ellieee]

Homework Statement:

qn (di)-> the graph is a v-t graph, so shouldn't we say "constant velocity" instead of "speed"?

Relevant Equations:

nil

 

[Doc Al]

Yes. It's better to describe it as constant velocity, as speed just describes the magnitude and not the sign. (I presume this is one-dimensional motion.)

 

[Delta2]

In motion in a straight line such as in your example, the concepts of velocity and speed are almost identical: If speed is x, then velocity will be x or -x. I repeat, this holds only in motion in a straight line, it does not hold for other motions e.g. circular motion.

 

[ellieee]

in a straight line

how can you tell it's in a straight line ?

 

[Delta2]

how can u tell it's in a straight line ?

I can not infer it from the given data (the screenshot of the graph isn't complete, doesn't completely show the text that describes the graph), somehow I thought it was given to you.

 

[Doc Al]

how can u tell it's in a straight line ?

Since they label it a velocity-time graph, where the velocity is constant it must be moving in a straight line. (Assuming it's labeled accurately.)