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? __________

Acceleration Notes  Acceleration Units: meters per second squared

Acceleration Notes  Acceleration (Vector): Rate that velocity is changing  Example #1: TimeVelocity 0 s0 m/s 1 s3 m/s 2 s6 m/s 3 s9 m/s First Differences THIS IS ___________________ ACCELERATION ( ______________ __________ )

Positive Acceleration Diagram  When acceleration was positive (speeding up), why did we fall backwards? STARTINGCHANGINGENDING

Acceleration Notes  Example #2 TimeVelocity 0 s7.5 m/s 1 s5.0 m/s 2 s2.5 m/s 3 s0.0 m/s First Differences THIS IS ___________________ ACCELERATION ( ______________ __________ )

Negative Acceleration Diagram  When acceleration was negative (slowing down), why did we fall forwards? STARTINGCHANGINGENDING

Acceleration Notes  Acceleration Equation:

Acceleration Notes  Calculate Acceleration  From 0s to 1s  From 1s to 3s TimeVelocity 0 s0 m/s 1 s3 m/s 2 s6 m/s 3 s9 m/s

Acceleration Notes  Calculate Acceleration  From 0s to 1s  From 1s to 3s TimeVelocity 0 s7.5 m/s 1 s5.0 m/s 2 s2.5 m/s 3 s0.0 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. VariablesGiven? V0V0 V a t GIVEN INFORMATION

Practice (EASY  MEDIUM)  A skateboarder goes from a standstill to a speed of 6.7 m/s in 12 seconds. What is their acceleration?  Circle what we are solving for above.  Fill out the GIVEN INFORMATION table. VariablesGiven? V0V0 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. VariablesGiven? V0V0 V a t GIVEN INFORMATION

Homework  Check PowerSchool for Exam Grade