NOTES PACKET Unit 1. One Dimensional Kinematics AP Physics 1 Name: Discuss video 1 and positives and negatives in physics

Transcription

1 Date In Class Homework to completed that evening (before coming to next class period) 8/16 Tues (A) Intro to AP Physics 1 Pre-assessment Watch: 1D Kinematics video 1. Representing Motion Verbally 8/17 Wed (A) Discuss video 1 and positives and negatives in physics Watch 1D Kinematics video 2. Representing Motion Visually Part I 8/18 Thur (B) 8/19 Fri (C) Graphing Motion Discussion and Interpreting x-t and v-t graphs Watch 1D Kinematics video 3. Representing Motion Visually Part II 8/22 Mon (A) Graphing Motion Discussion/Activity 8/23 Tue (B) 8/24 Wed (C) Cart and Buggy Lab ***need lab notebook Study for graphing quiz 8/25 Thur (B) 8/26 Fri (C) Quiz over graphing motion and lab discussion/work on packet Watch 1D Kinematics video 4 Kinematic equations 8/29 Mon (A) LSM Discuss Kinematic equations Watch 1D Kinematics video 5: Free Fall 8/30 Tues (B) 8/31 Wed (C) Discuss Free Fall video, air resistance and Activity 9/1 Thur (B) 9/2 Fri (C) In class work on packet and review for test 9/5 Mon Labor Day (NO School) Study for 1D test 9/6 Tue (B) 9/7 Wed (C) 1 D Kinematic Test Watch 2D Video 1. Vector addition and relative motion 1

2 Unit Objectives: 1. An observer in a particular reference frame can describe the motion of an object using such quantities as position, displacement, distance, velocity, speed, and acceleration. a. The student is able to express the motion of an object using narrative, mathematical, and graphical representations. b. The student is able to design an experimental investigation of the motion of an object. c. The student is able to analyze experimental data describing the motion of an object and is able to express the results of the analysis using narrative, mathematical, and graphical representations. 2. The acceleration is equal to the rate of change of velocity with time, and velocity is equal to the rate of change of position with time. a. The student is able to make predictions about the motion of a system based on the fact that acceleration is equal to the change in velocity per unit time, and velocity is equal to the change in position per unit time. b. The student is able to create mathematical models and analyze graphical relationships for acceleration, velocity, and position of the center of mass of a system and use them to calculate properties of the motion of the center of mass of a system. Video 1 Link: Textbook Reference: Video 1: Representing Motion Verbally Guided Notes: Read through the questions below, then watch the video, answer the following questions. Pause as needed. What is the difference between a vector and a scalar quantity? Questions: Define the following terms: Position Distance Displacement How are speed and velocity similar? How are speed and velocity different, include the equation for each: Speed: Velocity: (turn page) 2

3 Define: Average velocity: Instantaneous velocity: When are average and instantaneous velocity the same? What do positives and negatives mean in physics? What does it mean to have positive: Position: negative: Displacement: Velocity: Define Acceleration, provide the units as well as the equation: Define the two conditions for positive acceleration: Define the two conditions for negative acceleration: 3

4 Summarize: on the google form write a summary about what you learned from the video. Make sure to include; Information about the different between speed and velocity, the difference between instantaneous and average velocity, and what signs of velocity and acceleration mean about an objects motion. Problems to try before class (show your work below) & type you answers into the google form where indicated. 1. A group of students are observing another student walking. The student walks 70 m east and then 30 m west. Sally says that the student has a final positive position of 40 meters. Bruno says that the student has a positive displacement of 40 meters. Jordan says that the student has a distance of 100 meters. Which student(s) is correct and why? 2. True or False: A moving object can have increasing velocity with negative acceleration? Extra notes on verbal descriptions of motion. 4

5 Video 2: Textbook: Video 2: Representing Motion with Graphs Part I Guided Notes: Questions: What is a Motion Diagram/Map? How does a motion diagram look for an object that is: At constant speed: Speeding up: Slowing down: For this motion diagram: 1. Describe the motion of the car 2. Calculate the velocity of the car 3. Plot a position vs. time graph Calculate the slope of your graph? Does it concur with the calculated value from #2? What quantity does the slope of a position vs. time graph give? What is the slope on an x-t graph look like for an object of an object moving with constant positive velocity? Sketch the velocity vs. time graph for this object: 5

6 Sketch position and velocity vs. time graphs for an object moving in the negative direction: Draw a position vs. time graph for the following motion diagram that shown a car with increasing velocity: What is the slope on an x-t graph look like for an object of an object moving with changing positive velocity? Show the difference in calculation and using the graph to determine the average velocity of the car vs. the instantaneous velocity of the car at a particluar moment in time: Average Velocity Instantaneous Velocity 6

7 When are average and instantaneous velocity the same? When are they different? What are the two ways to generate a velocity versus time graph from a position vs. time graph that has changing velocity (slope) Why is the average in method 2 the midpoint of the time interval? Draw the velocity graph based off our data: How can you check to make sure you drew your graph correctly? What quantity does the slope of a velocity vs. time graph give? Summarize: on the google form write a summary about what you learned from the video. Make sure to include; How position vs. time graphs look for an object with constant velocity vs. one with changing velocity. The difference between average and instantaneous velocity for an object with changing velocity and what quantities the slope of an x-t and v-t graph give you. 7

8 WSQ Questions: Answer these questions on your WSQ google form Here is a motion diagram of a car moving along a straight road: 1. Which position-versus-time graph matches this motion diagram? 2. Which velocity vs. time graph matches the cars motion? E. None of these additional notes: 8

9 Recognizing Types of Slopes in class work: How can you tell if an object is moving faster on a position versus time graph? What is the difference between a graph of velocity when the line is above the x-axis vs. when it is below the x-axis? How can you tell if an object is speeding up or slowing down on a velocity vs. time graph? 9

10 A car moves along a straight stretch of road. The following graph shows the car s position as a function of time: At what point (or points) do the following conditions apply? The displacement is zero. The speed is zero. The speed is increasing. The speed is decreasing. How can you tell from a position vs. time graph if the speed/velocity is increasing or decreasing? 10

11 Video 3: Textbook: Video 3: Representing Motion with Graphs Part 2 Guided Notes: Questions: What are the three types of acceleration we will work with in this class and how does a a-t graph look for each scenario. Also describe what that means about velocity of the object Sketch 2 different scenarios of x-t and v-t graphs for an object speeding up and record the signs for velocity and acceleration: Sketch 2 different scenarios of x-t and v-t graphs for an object slowing down and record the signs for velocity and acceleration: What trick can use for to determine +/-/0 acceleration with positon vs. time graphs? Complete the following: 11

12 When can you use the area of a graph to find an unknown quantity? What is the area under a velocity vs. time graph? What is the area under an acceleration vs. time graph? Calculate the area under each segment of this graph and translate it to a position vs. time graph. How about this one: Summarize: on the google form write a summary about what you learned from the video. Make sure to include; The types of acceleration we will study in this class and how you can tell from a position vs. time graph the sign of acceleration. Also include information on what quantities can be obtained using the area on motion graphs. WSQ Questions: Answer these questions on your WSQ google form 1. Match a given velocity graph with the corresponding acceleration graph 12

13 2. Below is the velocity graph of an object that is at the origin (x 0 m) at t 0 s. At t 4.0 s, the object s position is A. 20 m B. 16 m C. 12 m D. 4 m In Class Notes: Fillout the following summary chart: Position vs. time Velocity vs. time Accel. Vs. time Instantaneous position Displacement Instantaneous velocity Change in velocity Instantaneous acceleration 13

14 Video 4: Textbook: Video 4: Kinematic Equations Guided Notes: Questions: Describe the characteristics of an object moving in uniform motion with constant velocity: include a motion diagram, graph and the equation to calculate velocity. What is the rearranged equation for position when the velocity is constant (a=0)? When an object is accelerating why can t you use v=δx/δt to calculate the velocity at any specific moment in time? Describe the characteristics of an object moving with NON-constant velocity and constant acceleration: include a motion diagram, graph and the equation to calculate velocity. What is the displacement equation for an object accelerating and what is the relationship between position and time? What are the steps for solving kinematic equations? 14

15 Example 1. A Saturn V rocket is launched straight up with a constant acceleration of 18 m/s 2. After 150 s, how fast is the rocket moving and how far has it traveled? Example 2. A airplane flying initially at 120 m/s lands on a carrier deck and stops in a distance of 91m. What is the acceleration? Summarize: on the google form write a summary about what you learned from the video. Make sure to include information about how the presence of acceleration effects which equations you can use for velocity and the problem solving steps for kinematic problems. WSQ Questions: Solve the following problems (show work below, answer in google form): Suppose that a car is moving with a speed of 18.5 m/s when the brakes are applied so as to slow the car down at a rate of m/s 2 ; 1. What will be the speed of this car 3.55 seconds after the brakes are applied? 2. How far will this car move during this 3.55 second period? 15

16 Video 5: Textbook: Video 5: Free Fall Guided Notes: Questions: What force acts on all objects on earth? In what direction is that force? How does mass affect the rate at which an object falls if air resistance is ignored? What is the value of free fall acceleration (acceleration due to gravity)? Draw a motion diagram for an object which is tossed up into the air and then falls back down. Include signs (+/-/0) for displacement, velocity and acceleration at all points. What are the up/down rules? A ball is thrown upward with a velocity of 20 m/s at point A. It reaches a maximum height at point B and then falls to 50 m below its starting position at point E. at point B: what is its velocity? what is its acceleration? at point C: what is its velocity? what is its acceleration? On the next page SKETCH and x-t, v-t and a-t graph of the balls motion. 16

17 X (m) Time (s) v (m/s) Time (s) a (m/s 2 ) Time (s) Solve: A heavy rock is dropped from rest at the top of a cliff and falls 100 m before hitting the ground. How long does the rock take to fall to the ground, and what is its velocity when it hits? 17

18 Solve: A stone is thrown vertically upward with a speed of 18 m/s. How long is required to reach a height of 11 m? Summarize: on the google form write a summary about what you learned from the video. Make sure to include the magnitude of the acceleration due to gravity and the up down rules. WSQ Questions (enter answers on the google form): An arrow is launched vertically upward as shown to the right. It moves straight up to a maximum height, then falls to the ground. The trajectory of the arrow is noted in the diagram. 1. At which point of the trajectory is the arrow s acceleration the greatest? The least? Ignore air resistance; the only force acting is gravity. 2. Which graph best represents the vertical velocity of the arrow as a function of time? Ignore air resistance. In Class Notes on Free Fall and Air Resistance: 18