speed...............?

Question

will speed always equal distance over time...or is it delta d over delta t?

Answer 1

Speed is a scalar quantity, meaning it has only a measurement, not a direction. Velocity is a vector quantity, meaning it has a measurement and direction; example 55 mph north.

speed would be distance over time. Velocity is the displacement over a certain time. This is actually average velocity, meaning delta d over delta t. How far away is the object from its inital starting point and how long did it take to get there?

Answer 2

Isn't that the same thing? The greek letter Delta means change. I am more familiar with Delta P because of my years working with pneumatics, but the distance traveled is the change of distance and the time it took to go that distance is the change of time. The only purpose I can see for using Delta is to place the information into a formula where the answer could be derived without realizing that you were talking about speed.

Answer 3

Delta just means the change of a given value - so delta d means the difference between the starting point (usually 0) and the distance to the final point - same with delta t, it's just how much time elapsed for the object to get to the final point.

Answer 4

Average speed is distance over time.
Instantaneous speed is delta d over delta t.

In other words the delta suggests the ratio of change in position with respect to a small increment of time.

j

Answer 5

Speed really is the change in distance over the change in time, or delta d over delta t.

Average speed is delta d/delta t
Instantaneous speed is a derivative dx/dt