Unit 2 (Motion & Forces), Day 2

Acceleration

Agenda Turn in Homework (0 min) Catalyst (5 min) Homework Explanation (5 min) Activity (20 min) Notes (10 min)

Notes Packet Write your name at the top of the packet DO NOT LOSE

Perhaps staple into notebook if necessary Remember, also glue/staple/tape PINK EQUATION

SHEET in

Student Entry Turn in “Speed & Velocity” Homework!

CATALYST:

Imagine you are on a bus. Describe how your body moves when: The bus is moving at a constant speed

The bus speeds up quickly

The bus slows down quickly

Homework Explanation

11 ft

19 ft

23 ft

31 ft

5 s

9 s

10 s

15 s

Accelerometer Activity Write your name on the bottom of the index

card

NAME: Mrs. Larkin

NAME:

Accelerometer Activity Tie string to center point of the accelerometer.

Mrs. Larkin

NAME:

Accelerometer Activity Tie a washer to the bottom of the string.

Mrs. Larkin

Accelerometer Activity

10 minutes

Stay in courtyard, be efficient

One chair per group, push each group member

Write observations down (see next slide)

Warnings

Don’t mess around

Don’t push chairs of sidewalk cracks

Do not push/stop hard enough to cause a person

to fall out

Accelerometer Activity Observations:

Speeding Up Quickly__________________________________________________________________________________________________________________________________________

Constant Velocity__________________________________________________________________________________________________________________________________________

Slowing Down Quickly__________________________________________________________________________________________________________________________________________

Comparison: Catalyst & Accelerometer

THINK

Finish your accelerometer activity observations

PAIR

Compare “Catalyst” responses with “Accelerometer”

observations

Speeding Up: Body? Washer?

Constant Speed: Body? Washer?

Slowing Down: Body? Washer?

SHARE

3 people called on randomly to respond to questions

Figuring Out an Equation Acceleration Unit Examples:

Meters per second squared

Feet per second squared

Kilometers per minute squared

What do the numerators have in common? __________ What do the denominators have in common?

__________

22/s

msm

22/s

ftsft

22

minmin/

kmkm

Acceleration Notes Acceleration Units: meters per second

squared

ss

m

s

msm

22/

Acceleration Notes Acceleration (Vector): Rate that velocity is

changing Example #1:

TimeVelocit

y0 s 0 m/s1 s 3 m/s2 s 6 m/s3 s 9 m/s

First Differences

THIS IS ___________________ ACCELERATION( ______________ __________ )

Positive Acceleration Diagram When acceleration was positive (speeding up),

why did we fall backwards?STARTING CHANGING ENDING

Acceleration Notes

Example #2

TimeVelocit

y0 s 7.5 m/s1 s 5.0 m/s2 s 2.5 m/s3 s 0.0 m/s

First Differences

THIS IS ___________________ ACCELERATION( ______________ __________ )

Negative Acceleration Diagram When acceleration was negative (slowing

down),why did we fall forwards?STARTING CHANGING ENDING

Acceleration Notes Acceleration Equation:

Acceleration Notes Calculate

Acceleration From 0s to 1s

From 1s to 3s

TimeVelocit

y

0 s 0 m/s

1 s 3 m/s

2 s 6 m/s

3 s 9 m/s

Acceleration Notes Calculate

Acceleration From 0s to 1s

From 1s to 3s

TimeVelocit

y

0 s 7.5 m/s

1 s 5.0 m/s

2 s 2.5 m/s

3 s 0.0 m/s

Acceleration Notes

Constant Acceleration:

Acceleration does not change as

time goes on (in other words,

first difference between equal

time spans should ALWAYS be

the same!)

Practice (EASY) As a school bus slows to a stop, it slows from

9.00 m/s to 0.00 m/s in 5.00 seconds. What is its acceleration? Circle what we are solving for above. Fill out the GIVEN INFORMATION table.

Variables

Given?

V0

V

a

t

GIVEN INFORMATION

Practice (EASY MEDIUM) A skateboarder goes from a standstill to a

speed of6.7 m/s in 12 seconds. What is their acceleration? Circle what we are solving for above. Fill out the GIVEN INFORMATION table.

Variables

Given?

V0

V

a

t

GIVEN INFORMATION

Practice (EASY MEDIUM) A sprinter increases from 5.0 m/s to 7.5 m/s

over a period of 1.25 seconds. What is their acceleration? Circle what we are solving for above. Fill out the GIVEN INFORMATION table.

Variables

Given?

V0

V

a

t

GIVEN INFORMATION

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