Albert Teen YOU ARE LEARNING:  Acceleration as a Vector  # Acceleration as a Vector ### Acceleration as a Vector

The "direction" of acceleration is whether acceleration is positive or negative.

Acceleration is a vector ** quantity*, which means it has both a magnitude and a direction.* Acceleration is a vector quantity, so it has both a magnitude and a direction

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This woman is going from a speed of $3 \space m/s$ to a speed of $7 \space m/s$. Is she speeding up or slowing down?  2

The woman is speeding up from $3 \space m/s$ to $7 \space m/s$

She does that over the course of just one second, so her acceleration is $4 \space m/s^2$ 3

Now the woman is going from a speed of $7 \space m/s$ to $3 \space m/s$. Is she speeding up or slowing down?  4

The woman is now slowing down again from $7 \space m/s$ to $3 \space m/s$

She does that over the course of just one second, so her acceleration is now $-4 \space m/s^2$ Acceleration's "direction"

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What do you think we mean by the "direction" of acceleration?  2

When an object is speeding up, acceleration is _______________.  3

When an object is slowing down, acceleration is _______________.  Summary!

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So the "direction" of acceleration refers to whether acceleration is positive or negative

If positive, like $4 \space m/s^2$, the object is speeding up. If negative, like $-4 \space m/s^2$, the object is slowing down. 