Do Now 1. If you drive at 68 mph for 5 hours, how

far would you travel?

2. You really want to drive to visit the Heat’s science teacher Ms. Lusk over the summer break. She lives in Washington State! If you travel at 70 mph for 24 hours, would you make it to WA? Why or why not? (p.s. How far do you think Washington is? Think critically!!!)

AnnouncementsNotebook Check on Friday

Pre-Lab Sheets will be handed out today…due back tomorrow to participate in lab

Test Corrections…turn into silver basket

Agenda:Some notes on Acceleration

Discovery Ed Acceleration Video Clip

Check for Understanding

Independent Work

Velocity and AccelerationSpeed it up!

AccelerationAcceleration is a change in velocity over time

Check for Understanding

What two components make up velocity?

Velocity

Speed Direction

Check for Understanding

AccelerationDef.: Change in _________ over ___________Can be change in speed or direction (speed up, slow down, or change direction)

AccelerationDef.: Change in _velocity_ over __time____Can be change in speed or direction (speed up, slow down, or change direction)

Check for Understanding

Is this ball accelerating?

Yes! Because the direction is changing.

Which cars are accelerating?

Cars B and C!

ABC

Acceleration

Acceleration is not just a change in velocity, it’s how fast that

change happens.

Which car has the greatest acceleration?

Car C!

ABC

Discovery Education Videohttp://player.discoveryeducation.com/

index.cfm?guidAssetId=A04DA40D-810B-4057-B333-7752AF27FAA2&blnFromSearch=1&productcode=US

Acceleration

To measure it, you must know the initial velocity, the final velocity,

and the time it takes to make the change.

AccelerationDef.: Change in velocity

Can be change in speed or direction

(speed up, slow down, or change direction)

Acceleration = ∆v/ t

Acceleration• Initial Velocity –Object’s velocity when you start measuring acceleration.

• Final Velocity –Object’s velocity when you finish measuring acceleration.

• - Greek letter delta – “change”

Acceleration

Acceleration = change in velocity

time

a= vt

The unit for acceleration is m/s2.

Acceleration

v is the difference between the final velocity (vf) and the

initial velocity (vi).

v = vf - vi

AccelerationDef.: Change in velocity

Can be change in speed or direction

(speed up, slow down, or change direction)

Acceleration = ∆v/ t∆v = vf – vi

Example 1A roller coaster’s

velocity at the top of a hill is 10m/s. Two seconds later it reaches the bottom of the hill with a velocity of 26m/s. What is the acceleration of the roller coaster?

Answervf = 26 m/s

vi = 10 m/s t = 2 s

Acceleration = ∆v/ ta = 26m/s – 10m/s

2 sa = 16m/s

2sa = 8m/s/s or 8m/s2

Examples 2-4 – Try them!2. A car travels at 60 miles per hour

around a curve. Is the car accelerating?

3. A car travels in a straight line at 60 mi/hr. Is the car accelerating?

4. A car goes from 0 mph to 60 mph in 6 seconds. What’s the car’s acceleration?

Answers:1. Yes! Because it’s changing direction.2. No! It’s not changing speed or direction.3. -vf = 60 mph

vi = 0 mph t = 6 s-a = vf – vi

t-a = 60 – 0 mph = 10 m/s2

6 s

Graphing Velocity vs. Time

Constant acc. No acc. Increasing acc.

Exit TicketWhat is the unit of acceleration?

Solve these problems:1. A car is traveling at a velocity of 24 km/hr

west and increases to a speed of 50 km/hr west in 4 seconds. What is the car’s acceleration?

2. Jade is walking to the store at a velocity of 5 km/hr. She realizes that the store is closing in a few minutes. She accelerates to running at a rate of 15 km/hour in 2 seconds. What is her rate of acceleration?