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V can take on a lot of meanings. In your case, it most certainly means velocity only. Not speed.

There is a difference between the two, and it is very important for determining what physics equations look like. This is because velocity is a vector quantity. By that, I mean velocity is defined both by its magnitude (speed) and its direction. Speed is only the magnitude of a velocity value.

Here's an example of how the two are different. Suppose you said that North is a positive direction. First, you travelled 2 miles north in 1 hour, then you travelled 2 miles south in 1 hour. If we were only talking about speed, your speed would be constant over your whole round trip: 2 mph. However, your velocity would change! Initially, your velocity would be 2 mph. However, when you turned around and headed south, your velocity became -2 mph! In fact, once you reach your start point and calculate your average velocity as we do below, you end up with a surprising result:

Average Velocity = Change in distance/change in time

Average Velocity = 0 / 2 hours = 0 mph

You get this result because overall you had no change in distance over time! However your speed showed you constantly moving, so you still have an average speed of 2 mph. In other words, speed doesn't care where you go as long as you are moving. Velocity is about how fast you are moving AND where you are going.

Side Note: When you were mentioning (Triangle)d/(Triangle)t, the triangle is a Greek letter capital Delta. Delta is used everywhere in science, and it is important because it represents the change in a given quantity. For example, Delta(d) = change in distance.

You can make further comparisons between the two in the links provided below.

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