Unit 3: 2-D Motion and Vectors Physics Fall 2015

Agenda 9/29 Turn in Dune Buggy Challenge Labs Intro to Vectors Nspire Activity Notes: Vectors Vector Exit Slip

Vectors We already know that vectors are measurements that tell us magnitude and direction. We also know how to examine vectors when they are in the x-direction (horizontal) or the y-direction (vertical). What happens when something is moving at an angle?

Vector Addition We must break down these angular vectors into their x and y components For example: R is my angled vector (resultant vector) V1 is my x-component V2 is my y component How should we determine the value of R?

Vector Addition How do we figure out the length of a hypotenuse of a right triangle? Good old Pythag!! a2 + b2 = c2 If v1 is 3 meters and v2 is 4 meters, what is the total displacement of the object as it moves the length of R?

Vector Addition How do we draw resultant vectors? Ex: If a person moves 6 meters east and then 8 meters north, what is their total displacement from where they started? + = 6 meters east 10 meters NE 8 meters north

Rules to adding Vectors Be sure to draw your vectors HEAD to TAIL. If you do not you will end up with the wrong R Be sure to draw your vectors differently based on their magnitudes (larger magnitude, larger vector). + = 6 meters east 10 meters NE

Agenda 9/30 Pirate Pythag Addition of Vectors PS

Agenda 10/1 Addition of Vectors Nspire Check-up Trig for Physics Get a hat!! Trig for Physics SohCahToa for angled vectors The PUKE Method Quiz Friday: Vector Addition

Angled Vectors For vectors that are not completely in the x or y direction, we must use trig!! Trig will allow us to “break up” an angled vector into its x and y components. We should probably review some trig!

Example Problem b = 8m α = 35o Find the remaining variables of the triangle.

Y- component X- component

Example Problem A person is looking up at a plane with an angle of 50o , using his range finder he finds out that this plane is 1200m from him. What is the plane’s height above the ground?

Agenda 10/5 Collect Take-Home Quizzes Notes: Half-Projectiles Breaking motion into components Problem Set: Half-Projectiles HW: Complete PS

Rolling Ball Demo You will roll a ball off of a table and your partner will drop a ball off of a table at the same time. Predict: Which ball will hit the floor first? Why? You need someone with a slo-mo camera in your group.

How can we explain this? We need to break the velocity of the ball into its VECTORS Rolling Ball Dropped Ball X-Velocity Y-Velocity ** The only vector that explains falling is the Y-Component, which is the same in this demo**

Still Don’t Believe Me? Let’s use our equations to prove it. A ball is dropped from 1m off of the floor with no initial velocity. How long until this ball hits the floor? A ball is rolled off of a 1m table with initial velocity in the x-direction of 1,000,000,000m/s, but no velocity in the y-direction. How long until the ball hits the ground?

The link between the X and Y Directions The time it takes the ball to fall from the table, is the same amount of time that the ball moves in the horizontal direction. So… ty = tx

Agenda 10/6 Notes/Practice Half-Projectile Problems Complete HP Problems in Class HW: Complete Projectile Problems

Agenda 10/7 Warm-Up Questions about Half-Projectile HW Rolling Ball Lab HW: Complete Rolling Ball Lab

Warm-Up A ball is rolled off of a .75m table with an initial velocity of .5m/s in the horizontal direction. How far away from the table will the ball land?

Rolling Ball Lab It will be your job to predict where the ball will land on the floor. You will determine the speed of the rolling ball (x-direction) You will determine how long it will take the ball to fall (y-direction) You will locate a range on the floor where your ball will land.

Agenda 10/8 2nd and 3rd Hour get a HAT Warm-Up Nspire Quiz: Half-Projectiles Review of Vector Addition Putting Problem Gilligan Problem

Go Cubs!! If Henry throws the ball 400ft to the catcher and the baseball drops a total 2.5m, how hard did Henry throw the ball?

Agenda 10/9 Get a Netbook and turn it on now!! Check Gilligan Problem Introduce Quarter Project Video Analysis of Sample Video What games are you going to try for the project!

Agenda 9/13 Let’s Go Outside and PLAY!! We need video cameras We need any kind of outdoor activity materials

Your group should have A video recording device A meter stick Any supplies necessary to complete your activity.

Agenda 10/15 Discuss Quarter 1 Project Intro to FULL Projectiles PhET You will need a Netbook and you will work with a partner When done: Get Nspire and complete Full Projectile questions

Agenda 10/16 Notes on Full-Projectiles PPT and Practice Problems Complete Practice Packet in Class Or complete for HW HW Quiz Monday?? Quarter 1 Project Due: October 29th

Full Projectile Shape The x and y directions are independent of each other still. Gravity is still the only FORCE acting on the projectile.

Half- Projectile Equations X-Direction Equation(No acceleration) v = d/t Can we use this one for vertical motion?? Y-Direction Equations (Acceleration due to Gravity) g = (vf - vi ) / t yf = yi + vit +1/2 gt2 vf = vi + gt vf2 = vi2 + 2gyT Remember that the link between the two is… ty = tx

New Full-Projectile Equations All of the half-projectile equations are true, and then some! tup = tdown vyi = vyf v1/2 = 0m/s = vpeak

Agenda 10/19 Homework/Notes Check Full-Projectile Example Complete Full Projectile Problem Set Quiz Tomorrow: Trig problems Half-Projectile Problems Full-Projectile Problems

Homework Quiz At what point is the vertical velocity equal to zero? D B A E At what point is the vertical velocity equal to zero? At what points are the horizontal velocities equal? At what point(s) is the vertical velocity the greatest?

Full Projectile Example A football is kicked with an initial velocity of 15m/s at a 50o angle. What is the initial vertical velocity? How long will it take the football to reach its peak height? What is the initial horizontal velocity? What is the total range of the football? (horizontal distance)

Agenda 10/20 Quiz: Trig, Half and Full Projectiles Pre-Lab: Full Projectile Challenge Lab Calculations for Pre Lab Test Thursday!

Agenda 10/21 Warm-Up Full Projectile Challenge Lab Review for Test Get Nspire and HAT Full Projectile Challenge Lab Pre-lab checked by Gustin Review for Test T/F Assessment about Projectiles HW: Study for Test Tomorrow

Agenda 10/22 Test on Unit 3

Agenda 10/23 Final Work Day IN-CLASS 2nd Hour: Room 217 3rd Hour: In Classroom 5th Hour: Room 259