Acceleration Part 3 – World Winning Rube. Review In previous learning we have looked at the differences how objects can move: Speed vs. Velocity However,

Acceleration

Part 3 – World Winning Rube

Review

• In previous learning we have looked at the differences how objects can move:• Speed vs. Velocity • However, these don’t tell us very much.

Speed is a snapshot of how fast an object is going in an instant. Velocity showed us that more likely, objects are measure over an extended period of time.

Average Car Travel

• Although speed and velocity help to describe motion, they leave out a lot of information.

• Think of a typical drive to school. • Driveway to residential street –• Residential street to stop sign –• Stop sign to major street –• Major street to stopping at the school -

ACCELERATION

• The change of velocity of an object over time. • Think of when we learned about velocity, all we are

doing is adding how much time it took to change the velocity .

• A vector, therefore there is direction (or + or - ) of motion and a number value .

• Examples...• Car accelerates from 0km/hTo 60 km/h in 30 seconds!

• An object is accelerating if it is changing its velocity.

• Sometimes an object can be accelerating and getting faster, or an object can be decelerating and slowing down.

• Think of a car at a stop light:– When it sees the red light it is decelerating and

when it sees the green light after being stopped it starts to accelerate.

• http://www.physicsclassroom.com/Class/1DKin/U1L1e.cfm

FORMULA FOR ACCELERATION

• Acceleration is measured in 2 quantities:• The change of the velocity of an object in the amount

of time.

• In order to calculate acceleration in this time, we simply take the second velocity value, subtract the first velocity value and divide by total time.

FORMULA FOR ACCELERATION

• If we were to look at the velocity of an object over time, we can see that this object is constantly accelerating.

• The velocity in m/s increases by 10, each second of time that passes.

• If we were to plug in the value of the first and last velocity, we well as the total time, this is the formula we would get:

ACCELERATION UNITS

• If we look at the final math for our last example, you can see that we get velocity over time.

• Therefore our final units are actually:– m/s/s or m/s2

– km/h/h or km/h2

Check Your Understanding

• To test your understanding of the concept of acceleration, consider the following charts and plug them into the acceleration formula. Use the equation for acceleration to compare the accelerating of the 2 objects.

Check Your Understanding

• Practice A:

• Practice B:

• Comparison: