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# Acceleration

Introduction: Imagine you're in a car, traveling at 30 miles per hour east, away from Manhattan. If you decide to "speed up", changing to 60 miles per hour east, away from Manhattan, you are experiencing acceleration. Even if you decided to drive into a parking lot in Manhattan without changing how fast you traveled and decided to travel in a circle, you would still be accelerating. This is because acceleration is what is known as a vector quantity, or a quantity with an associated magnitude and direction.

Acceleration, in particular, refers to the change in the velocity of an object over time. Acceleration can be found by considering the initial velocity, the final velocity, and the time period in which this velocity changed. To have a positive sign for acceleration means that one is accelerating, or experiencing a positive change in velocity over time. On the other hand, to have a negative sign for acceleration means that one is decelerating, or experiencing a negative change in velocity over time.

The equation for acceleration is summarized as follows:

a=∆v/t, where a=acceleration, ∆v=change in velocity=final velocity - initial velocity, and t=time

Based on the equation above, since the standard unit for velocity is m/s and since the standard unit for time is s, the standard unit for acceleration is m/s/s, or $"m"/"s"^2$. This is important to consider when expressing acceleration in physics to the proper units. When expressing acceleration, it is also important to mention the direction of the acceleration, since acceleration is a vector quantity.

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