Can you use speed and velocity interchangeably?

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Speed and velocity are closely related concepts, particularly in one-dimensional motion, where they can often be used interchangeably. Speed refers only to magnitude, while velocity includes direction, which is crucial for understanding motion. In a straight line, if speed is x, velocity can be either x or -x, but this relationship does not apply to other types of motion, such as circular motion. The discussion highlights the importance of accurately interpreting graphs, particularly velocity-time graphs, to determine the nature of the motion. Accurate labeling of such graphs is essential for confirming that the motion is indeed linear.
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Homework Statement
qn (di)-> the graph is a v-t graph, so shouldn't we say "constant velocity" instead of "speed"?
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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.)
 
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.
 
Delta2 said:
in a straight line
how can you tell it's in a straight line ?
 
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ellieee said:
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.
 
ellieee said:
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.)
 

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