9/20/15 Calculating Acceleration & velocity We will calculate an object’s velocity and acceleration. I will take a quiz to demonstrate my ability to Calculate an object’s velocity and acceleration. *You need the Socrative App, calculator& piece of scratch paper for quiz

Bell Ringer Happy birthday Mrs. Lee Calculate the object’s acceleration from the diagram for leg A,B, & C of the journey. What is happening at A,B & C? 48

What is velocity? Meanings V- velocity X0- initial position X- final position Δ t- change in time ( tf-ti)

What is acceleration? The rate of change of an objects velocity over time taken. Meanings a- acceleration V- final velocity V0- initial velocity t- change in time ( tf-ti)

Lesson Objectives We will calculate an object’s displacement, velocity and acceleration. I will take a quiz to demonstrate my ability to Calculate an object’s velocity and acceleration. *You need the Socrative App, calculator& piece of scratch paper for quiz

AGENDA Bell Ringer Identify the variables by units Fill out physics variable units sheet ( tape/attach to notebook) Examples 1,3,6 - Whole class Practice 2,4,5 -Partner/small group Complete 7,8,9,10 – Independent SOC QUIZ

HAPPY EARLY BDAY ALIX!!

Meters per second (m/s) Velocity (final) Variable Units Name Notes: t Seconds , (s) Time  can also be min or hr d Meters (m) Distance   x Meters (m) displacement v Meters per second (m/s) Velocity (final) v0 m/s Velocity (initial) a m/s2 acceleration g Acceleration due to gravity(free fall) g = 9.8 m/s2 Δ none Delta Means ‘change in’ i.e final - initial Velocity Equation v = Δx/Δt; Acceleration Equation a = Δv/Δt; a= v - v0 Kinematic Equations v = v0 + at v2 = v02 + 2ax x = v0t + ½ at2 x = ½(v + v0)t

Match the Variables by units 50m/s 56m/s2 34Km/h 40s 67m acceleration Speed/velocity Time Distance/displacement

Match the Variables by units 50m/s 56m/s2 34Km/h 40s 67m 45 km acceleration Speed/velocity Time Distance/displacement

Formulas Formulas: 2 3 1 Which formula would I use for displacement? 3 Which formula would I use for displacement? Which would I use for acceleration? Which would I use for velocity? 1

Formulas Formulas: 2 1 3 Which formula would I use for displacement? 1 Which formula would I use for displacement? Which would I use for acceleration? Which would I use for velocity? 3

Problem#1 The fastest airplane is the Lockheed SR-71. If an SR-71 flies 15.0 km west in 15.3 s, what is its average velocity in kilometers per hour? Looking for: Given: Relationship/ Formula:

Problem#1 The fastest airplane is the Lockheed SR-71. If an SR-71 flies 15.0 km west in 15.3 s, what is its average velocity in kilometers per hour?

Problem #3 3. Heather and Mathew walk with an average velocity of 0.98 m/s eastward. If it takes them 34 min to walk to the store, what is their displacement?

Problem #6 A shark accelerates uniformly from 2.8 km/h to 32.0 km/h in 1.5 s. How large is its acceleration in km/hr2?

Solutions-Problem 2 A snail can move about 4 m in 5 min. Whats the average speed of the snail in m/s? d= 4 m t= 5 min= 5min*60s/1min = 300 s s=? s= d/t = 4m/300s = 0.013 m/s

Solutions-Problem 4 Simpson drives his car with an average velocity of 48 km/h east.How long will it take to drive 144 km.? v= 48 km/h d=144 km t=? t=d/v t= 144/48 = 3 hr

Solutions-Problem 5 A rocket sled comes to a complete stop from a speed of 320 km/h in 0.18s. What is the sled’s average acceleration in km/h2? vf=0 km/h vi=320 km/h t= 0.18s (*1hr/3600s)= 0.00005hrs a= ? a= 0- 320 =-6,400,000 km/h2 OR 0.00005 (-6.4 X106 km/h2)

QUIZ TIME *You need calculator, Socrative app (LEE346), scratch paper, pen/pencil 1. Socrative Quiz 2. You can use your variables & units chart Sign in as : First name,Lastname YOU CAN ONLY DO the QUIZ ONCE!!! If you have an issue let me know IMMEDIATELY!

Explaining acceleration pictorially, graphically & with words Acceleration intro Explaining acceleration pictorially, graphically & with words

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Lesson Objectives We will describe an objects motion in terms of its acceleration. With my group, I will create a story, a picture, and a graph that depicts the motion of a person that as: A. No acceleration. C. Constant + acceleration D. Constant - acceleration

Describing with words The gun goes off. The runner takes off. He steadily speeds up at a rate of 2 m/s2. After 2 seconds he’s burned out. His speed stays the same for about two seconds then Momma yells from the crowd,” Don’t you quit!!”He had nothing left. He runs slowly to the finish line.

Graphically

All 3 graphs connected

Graph Practice Try making all three graphs for the following scenario: 1. Newberry starts out north of home. At time zero he’s driving a cement mixer south very fast at a constant speed. 2. He accidentally runs over an innocent moose crossing the road, so he slows to a stop to check on the poor moose. 3. He pauses for a while until he determines the moose is squashed flat and deader than a doornail. 4. Fleeing the scene of the crime, Newberry takes off again in the same direction, speeding up quickly. 5. When his conscience gets the better of him, he slows, turns around, and returns to the crash site.