Question

what two things do you need to know to find somethings speed? what is the word for the rate at which speed changes?

Explanation:

Step1: Recall the speed formula

Speed \(v=\frac{d}{t}\), where \(d\) is distance and \(t\) is time. So to find speed, we need distance and time.

Step2: Recall the definition of acceleration

Acceleration \(a\) is defined as the rate of change of velocity (and speed, when motion is in a straight - line without direction change). The formula for acceleration is \(a = \frac{\Delta v}{\Delta t}\), where \(\Delta v\) is the change in velocity (or speed in one - dimensional motion without direction change) and \(\Delta t\) is the change in time.

Answer:

To find something's speed, you need to know distance and time. The word for the rate at which speed changes is acceleration.