Presentation on theme: "Physics: Principles and Problems. ACT/PSAE practice Intro to acceleration – What does it mean in common language? – What does it mean to a physicist?"— Presentation transcript:
Physics: Principles and Problems
ACT/PSAE practice Intro to acceleration – What does it mean in common language? – What does it mean to a physicist? (That’s you!) First equation of acceleration – A = v/t – Standard unit for acceleration: m/s^2 Example Problem HW: Acceleration WS #1 – Be sure to convert km/h to m/s!
What is acceleration? When am I accelerating? Is acceleration a scalar or vector? How do I solve a physics problem involving Acceleration? What does a position-time graph of acceleration look like? What are velocity-time graphs, and how can I find distance travelled and instantaneous acceleration
What does it mean to you in common conversation? What is the book’s definition? “Deceleration” is just acceleration in a negative direction
______ is riding their bike to school. They
1. You run the 100 meter dash with an average velocity of 8 m/s. How long does it take you to finish? 2. Make a position-time graph of the following motion diagram: (Line shows meters) (Hint: how long did it take to go 10 meters?) 3. If your car can accelerate from rest to 20 m/s in 4 seconds, what is its acceleration?
When you fall, do you fall at a constant rate or accelerated rate? How do you know? Use complete sentences (UCS).
Is acceleration a scalar or vector? How do you know? Use complete sentences (UCS).
Collect Reaction Time Lab Bellringer Introduce Acceleration Equation #2: ◦ THE MONSTER! ◦ df = ½ a* t^2 + Vyi * t + di ◦ Example Problem Acceleration WS #2 ◦ Due Wednesday EQ: How does acceleration affect distance travelled?
Already know: Acceleration = (Vf – Vi) / t How do we find displacement? Df = ½ a * (t)^2 + Vi * t + Di ◦ Df = ◦ a = ◦ t = ◦ Vi = ◦ Di = What kind of equation/relationship/graph is this?
If your car can accelerate at 5 m/s 2, how long will it take the car to accelerate from 10 m/s to 25 m/s?
Bellringer Graphing Assignment Acceleration WS 2 pushed back to Thursday (for this class only)
Draw a position time graph of the following: ◦ 1. An object travelling at a constant velocity ◦ 2. An object that is not moving (start it at a position other than zero so we can see the line) ◦ 3. An object travelling that changes its velocity. Make sure to label your axes!
Collect Acceleration WS 2 Lab: Speed Freaks 2.0 ◦ Go to the FOOTBALL FIELD! Essential Questions: ◦ What does acceleration look and feel like? ◦ How do we calculate speed and acceleration?
Introduce ‘g’ ◦ -9.8 m/s^2 Hang Time Lab ◦ Finish by tomorrow first thing! Essential Questions: ◦ Does gravity pull things down at a constant velocity or accelerated? At what rate? ◦ How does gravity affect how I jump?
Collect Ch 2.2 Reading Guide Learn Breaking Distance Equation Problem Reading Trainer Accelerated Problem Poster Project ◦ Buy a poster this weekend. In fact, buy 5 posters. ◦ Show Examples Project: Make a parachute for an Egg ◦ Make it out of anything. Paper / plastic bags, newspaper String, tape, glue, staples Empty cartons for basket ◦ Project Rubric Next Week
This equation is used when time is not involved (not given or asked for) Vf^2 = Vi^2 + 2 * a * d Notice: no time! ______ is about to crash into _______. Their velocity is ________. If the cars are ______m apart, what acceleration do they need to have to avoid a crash?
CHAPTER 2CHAPTER 3 Velocity = disp. / time ◦ V avg = d / t ◦ Constant Velocity means no acceleration.. Use this forumla! Standard unit for velocity is m/s A = Vf – Vi / t Df = ½a*t 2 + Vi*t + di ◦ Shortcut: t = sqrt(2*d/a) ◦ Only to be used when falling and Vi = 0. Vf^2 = Vi^2 + 2 * a * d Acceleration due to gravity : g = -9.8 m/s 2 ◦ “fall, thrown, drop? Use g”
Collect Corrected Work ACT/PSAE Practice Distribute Problem Reading Trainer Essential Questions: What are the common elements to solving a physics problem?
A ball rolls horizontally at 6 m/s. How long will it take the ball to cover 30 meters? A ball rolls off of a table. It falls for 1 second before hitting the ground. How tall is the table? Make a p-t graph of someone walking forward for 2 seconds, stopping for 2 sec, and backwards for 2 sec. Extra credit: make a velocity-time graph of this too!
BellringerAgenda A football is thrown down field. It is caught at the same height that it was thrown. It is thrown at 20 m/s. How fast is it going when it is caught? Write in 1-3 complete sentences HOW DO YOU KNOW?!? Bellringer Interim Assessment #1 ◦ Do not write on the test ◦ You must bubble in Name and ID ◦ You MUST WRITE at the top: “Hedden Period _” ◦ Pass back work Go over the toughest assignment
Used for Right triangles only Involves Sine, Cosine, and Tangent Can be used to find an angle or side of a triangle by using two other parts of the triangle. Pythagorean Theorem a 2 + b 2 = c 2 SOH CAH TOA