Acceleration baby!!!!

So what is acceleration?

The rate of change in velocity (and also a change in direction).

Speeding up or slowing down

It's basically just change in velocity over time.

A Common Misconception...Sports announcers will Sports announcers will occasionally say that a person occasionally say that a person is accelerating if he/she is is accelerating if he/she is moving fast. Yet acceleration moving fast. Yet acceleration has nothing to do with going has nothing to do with going fast. A person can be moving fast. A person can be moving very fast and still not be very fast and still not be accelerating. Acceleration has accelerating. Acceleration has to do with to do with changingchanging how fast how fast an object is moving. an object is moving.

Describe in your notes an example of acceleration you

have experienced.

So why do you So why do you think you think you were were

accelerating? accelerating? (Explain in scientific (Explain in scientific

terms)terms)

So I bet you want the formula now don't you?!

Acceleration = Final Velocity – Initial Velocity

Time

The units of acceleration are expressed in velocity units per time units. For example, all of

these are units for acceleration:

m/s/s OR m/s2

mi/hr/s

km/hr/s

(the black part is the unit for velocity and the red is the time unit)

So here's our example problem that we'll work through together:

Acceleration = Velocity(final) – Velocity(initial) TimeThe final velocity is 26m/sec and the initial velocity is 10m/sec (the key word here is LATER!!!)

Acceleration = 26m/s – 10m/s = 16m/s 2s 2s

So using our acceleration formula we find the roller coaster's acceleration to be 8.0m/s2

Now turn to the person sitting next to you and explain to them the units

used for acceleration.

Why do you think acceleration is given in these terms?

We kind of hinted at this earlier, but is all acceleration positive? Why do you think

that?

DECELERATION Can you think of an example of

deceleration? Share your example with the person in

front of you and discuss your answers.

NO!!! Not all acceleration is positive. Some can be negative and we call

negative acceleration..............................................

.

What is happening to an object that is first accelerating, then decelerating?

It speeds up (increasing in velocity)

Then it slows down (decreasing in velocity)

Keep in mind, deceleration is calculated the same way as acceleration except that it is a NEGATIVE number! (it's basically negative acceleration!)