Do Now Complete this on your Daily Organizers: Is it possible for an object to move at a high speed for 10 seconds without any change in average velocity? How is it possible, or why is it not? You have to drive into town to take care of some errands. Would you expect to always have the same velocity? Why or why not? If the lake is 12 miles away from town and it takes you 48 minutes to reach town, what is your average velocity in miles/min?

Today’s Agenda Do Now Important Dates Acceleration Exit Ticket 5 min

Today’s Agenda Do Now Important Dates Acceleration Exit Ticket 5 min

Important Dates & Reminders Homework This Week HW assigned today is the last for the quarter  Grades and Extra Credit All grades updated in TeacherEase All assignments and extra credit due Wednesday Quiz Tomorrow on Speed & Velocity Difference between Speed & Velocity Finding Speed, Distance and Time using the equation Fall Break Oct. 11 – 14  Flag Football Game Saturday

Today’s Agenda Do Now Important Dates Acceleration Exit Ticket 5 min

Acceleration Speed it up! http://www.youtube.com/watch?v=0WpNSImh6Z8

Acceleration Def.: Change in velocity

Check for Understanding What two components make up velocity?

Check for Understanding Velocity Speed Direction

Acceleration Def.: Change in velocity 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? B C Cars B and C!

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

Which car has the greatest acceleration? B C Car C!

Acceleration To measure it, you must know the initial velocity, the final velocity, and the time it takes to make the change.

Acceleration Acceleration = ∆v/ t Def.: Change in velocity Can be change in speed or direction (speed up, slow down, or change direction) Acceleration = ∆v/ t

 - Greek letter delta – “change in” Acceleration Initial Velocity – An object’s velocity when you start measuring acceleration. Final Velocity – An object’s velocity when you finish measuring acceleration.  - Greek letter delta – “change in”

Acceleration = change in velocity time The unit for acceleration is m/s2.  v a = t

Acceleration v is the difference between the final velocity (vf) and the initial velocity (vi). v = vf - vi

Acceleration can be positive or negative. If the object is “speeding up,” then the acceleration of the object is positive. The change in velocity is an increase Ex: 5 mph North to 10 mph North If the object is “slowing down,” then the acceleration of the object is negative. The change in velocity is a decrease Ex. 5 mph North to 0 mph North

Acceleration Acceleration = ∆v/ t Def.: Change in velocity a = vF – vI Can be change in speed or direction (speed up, slow down, or change direction) Acceleration = ∆v/ t a = vF – vI t

Example 1 A 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?

Answer vf = 26 m/s vi = 10 m/s t = 2 s Acceleration = ∆v/ t a = 26m/s – 10m/s 2 s a = 16m/s 2s a = 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 20 m/s to 50 m/s 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 = 50 m/s vI = 20 m/s t = 6 s a = vf – vi t a =5 m/s2

What if I’m not looking for a? You can also find Vf, Vi and t using the same equation! (We’ll only do Vf and t though) Set it up with what you know and SOLVE. Example: A bug is accelerating at a rate of 2 m/s2. If it started at rest (0 m/s), how long will it take it to get to 6 m/s?

Example A bug is accelerating at a rate of 2 m/s2. If it started at rest (0 m/s), how long will it take it to get to 6 m/s? A = VF – VI 2 m/s2 = 6 m/s – 0 m/s t t

Example A bug is accelerating at a rate of 2 m/s2. If it started at rest (0 m/s), how long will it take it to get to 6 m/s? A = VF – VI 2 m/s2 = 6 m/s – 0 m/s t t 2 m/s2 = 6 m/s t

Example A bug is accelerating at a rate of 2 m/s2. If it started at rest (0 m/s), how long will it take it to get to 6 m/s? A = VF – VI 2 m/s2 = 6 m/s – 0 m/s t t 2 m/s2 = 6 m/s t = 6 m/s t 2 m/s2

Example: Finding Time T = 3 s A bug is accelerating at a rate of 2 m/s2. If it started at rest (0 m/s), how long will it take it to get to 6 m/s? A = VF – VI 2 m/s2 = 6 m/s – 0 m/s t t 2 m/s2 = 6 m/s t = 6 m/s t 2 m/s2 T = 3 s

Example: Finding VF Let’s say you wanted to find the final velocity. A ball has a an acceleration of –2 m/s2. It starts out at 12 m/s. What will be its velocity after 3 seconds?

Example: Finding VF Let’s say you wanted to find the final velocity. A ball has a an acceleration of –2 m/s2. It starts out at 12 m/s. What will be its velocity after 3 seconds? What does having a negative velocity mean?

Example: Finding VF Let’s say you wanted to find the final velocity. A ball has a an acceleration of –2 m/s2. It starts out at 12 m/s. What will be its velocity after 3 seconds? How do we set this problem up?

Example: Finding VF 2 m/s2 = VF – 12 m/s 3 s Let’s say you wanted to find the final velocity. A ball has a an acceleration of –2 m/s2. It starts out at 12 m/s. What will be its velocity after 3 seconds? How do we set this problem up? 2 m/s2 = VF – 12 m/s 3 s

Example: Finding VF 2 m/s2 = VF – 12 m/s 3 s 6 m/s = VF – 12 m/s Let’s say you wanted to find the final velocity. A ball has a an acceleration of –2 m/s2. It starts out at 12 m/s. What will be its velocity after 3 seconds? How do we set this problem up? 2 m/s2 = VF – 12 m/s 3 s 6 m/s = VF – 12 m/s

Example: Finding VF 2 m/s2 = VF – 12 m/s 3 s 6 m/s = VF – 12 m/s Let’s say you wanted to find the final velocity. A ball has a an acceleration of –2 m/s2. It starts out at 12 m/s. What will be its velocity after 3 seconds? How do we set this problem up? 2 m/s2 = VF – 12 m/s 3 s 6 m/s = VF – 12 m/s VF = 6 m/s

Guided Practice For the following guided practice problems, we will be using the multiple choice notecards. Grab a stack for you!

MC 1 What will cause acceleration? Speeding Up Slowing Down Changing Direction Any of the above

MC 1 Answer What will cause acceleration? Speeding Up Slowing Down Changing Direction Any of the above

MC 2 What are the units for acceleration? m m/s m/s2 s

MC 2 Answer What are the units for acceleration? m m/s m/s2 s

MC 3 If an object starts at rest and ends at 10 m/s, what is its initial velocity? 0 m/s 5 m/s 10 m/s Not enough information

MC 3 Answer If an object starts at rest and ends at 10 m/s, what is its initial velocity? 0 m/s 5 m/s 10 m/s Not enough information

MC 4 Emanuel speeds up from 4 m/s to 8 m/s in 2 seconds. What was Emanuel’s acceleration? 2 m/s2 -2 m/s2 4 m/s2 -4 m/s2

MC 4 Answer Emanuel speeds up from 4 m/s to 8 m/s in 2 seconds. What was Emanuel’s acceleration? 2 m/s2 -2 m/s2 4 m/s2 -4 m/s2

MC 5 A car accelerates from 10 m/s to 50 m/s in 5 seconds. What is the car’s acceleration? 5 m/s2 8 m/s2 10 m/s2 40 m/s2

MC 5 Answer A car accelerates from 10 m/s to 50 m/s in 5 seconds. What is the car’s acceleration? 5 m/s2 8 m/s2 10 m/s2 40 m/s2

MC 6 If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? What is his initial velocity? 0 m/s 0.5 m/s 1.5 m/s 3 m/s

MC 6 Answer If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? What is his initial velocity? 0 m/s 0.5 m/s 1.5 m/s 3 m/s

MC 7 If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? What is his final velocity? 0 m/s 0.5 m/s 1.5 m/s 3 m/s

MC 7 Answer If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? What is his final velocity? 0 m/s 0.5 m/s 1.5 m/s 3 m/s

MC 8 If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? What is his acceleration? 0 m/s2 0.5 m/s2 1.5 m/s2 3 m/s2

MC 8 Answer If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? What is his acceleration? 0 m/s2 0.5 m/s2 1.5 m/s2 3 m/s2

MC 9 If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? Now, answer the question  0 m/s 1.5 m/s 3 m/s 6 m/s

MC 9 Answer If Brandon starts at rest and accelerates at 0.5 m/s2, how long does it take him to reach his top speed of 3 m/s? Now, answer the question  0 m/s 1.5 m/s 3 m/s 6 m/s

MC 10 A snowmobile has an initial velocity of 3 m/s. If it accelerates at a rate of 0.5 m/s2 for 7 seconds, what is its final velocity? 1.5 m/s 3.5 m/s 6.5 m/s 10.5 m/s

MC 10 Answer A snowmobile has an initial velocity of 3 m/s. If it accelerates at a rate of 0.5 m/s2 for 7 seconds, what is its final velocity? 1.5 m/s 3.5 m/s 6.5 m/s 10.5 m/s

Independent Practice Complete the three independent practice problems on the back of your Daily Organizers. We will also continue practicing this tomorrow in addition to doing a lab  If you can go from 10 m/s to 70 m/s in 6 seconds, what is your acceleration? You are speeding in your car on I-40. You see a cop (uh oh). You are going 40 m/s (90 mph). You decelerate (slow down) at a rate of -6 m/s2. How long will it take you to get down to 31 m/s (70 mph – the speed limit)? An ice cream truck is moving along at 10 m/s. It then speeds up at a rate of 5 m/s2 for 3 seconds. What is the truck’s final velocity?

Today’s Agenda Do Now Important Dates Acceleration Exit Ticket 5 min

Exit Ticket Exit tickets will be my daily way of seeing whether or not you have understood the objectives we have gone over during class each day. They will NOT be graded for accuracy but WILL be graded for completion so make sure you always try each and every question. These exit tickets must be done silently and independently. If you violate this, you will lose your participation points for the day. You must wait to begin your exit ticket until Ms. Kemal says to begin.

Exit Ticket While drag racing out of our school parking lot, I time myself at a speed of 42 m/s after 7 seconds. What was my acceleration during this time? If I start at rest and then accelerate at a rate of 3 m/s2 for 9 seconds, how fast would I be going? If I were to drop a ball out of my car while I was traveling at a velocity of 25 m/s, and it underwent an acceleration of -5 m/s2 while rolling to a stop, how long would it take for it to stop?

Exit Ticket Answers Acceleration = (42 m/s) / 7 s = 6 m/s2 vF = at = (3 m/s2)(9 sec) = 27 m/s 12.5 s