Acceleration intro

Explaining acceleration pictorially, graphically & with words

Bell Ringer 9/18/15

• Calculate the object’s acceleration from the diagram for leg A of the journey.

What is this graph

showing? What does

acceleration mean?

What is acceleration?

• The rate of change of an objects velocity over time taken.

Meaningsa- accelerationV- final velocityV0- initial velocity t- change in time ( tf-ti)

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 PracticeTry 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.

9/24/15Calculating 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 9/24/15

• 1st-4th period:• Complete your lab conclusion/questions in 5

minutes.

• Remember: • average acceleration• is change in velocity divided by change in time

Bell Ringer 9/24 (6th-9th)

• 1. Download the Socrative app if you don’t already have one.

• 2. Find & Write down the formulas for:

• Speed= • Acceleration=• Velocity=

Lesson Objectives

• 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

Formulas

• Formulas:

Meaningsx= displacement = distancea- accelerationV- velocity= speedV- final velocityV0- initial velocity ∆t- change in time ( tf-ti)

0

1

2

3

Match the Variables by units

• 50m/s • 56m/s2

• 34Km/h• 40s• 67m

• acceleration• Speed/velocity• Time• Distance/displacement

Identifying Variables by units

• 50m/s • 56m/s2

• 34Km/h• 40s• 67m

• Velocity• Acceleration• velocity• Time• Distance/displacement

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?

Agenda 9/25/15• *You need calculator,

Socrative app (LEE346), scratch paper, pen/pencil

• 1. Socrative Quiz• 2.Grading 9/25

Worksheet Problems• 3. Exit Ticket –

question? Use parking lot

• Sign in as :• First name,Lastname

• YOU CAN ONLY DO the QUIZ ONCE!!!

• If you have an issue let me know IMMEDIATELY!

Formulas

• Formulas:

Meaningsx= displacement = distancea- accelerationV- velocity= speedV- final velocityV0- initial velocity ∆t- change in time ( tf-ti)

0

1

2

3

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)