Begin working silently on your article of the week. When you finish, you may read a book from the bookshelf.

Agenda: Homework sheet due Friday. Warm Up Ms. Coakley pointed to an apple sitting on her desk. She asked her students to describe any forces acting on the apple. This is what some of her students said. Archie: “The only force acting on the apple is air pressure.” Sam: “There is one force acting on the apple. Gravity is the force that pulls on the apple.” Soledad: “There are two forces: the desk pushes up on the apple and gravity pulls downward on the apple.” Misha: “There are many forces acting on the apple; but, it is the holding force in the apple that keeps it on the desk.” Tess: “There are no forces acting on the apple because the desk stops any forces from acting on it.” Which student do you most agree with? Explain your thinking. What rule or reasoning did you use to decide if there were any forces acting on the apple?

Motion What we know Definition: A change in position over time The ball moved from position 6 to position 3. 1 2 3 4 5 6 7 8 9

Reference Point WHAT: A location to which you compare other locations. WHY: They help determine if an object is in motion. The ball moved from position 6 to position 3. What is the reference point in the example? 1 2 3 4 5 6 7 8 9

What is a reference direction? A direction used to describe motion. What are examples of a reference direction? North, south, east, west, up or down

Notebook Title: Position vs. Time Enough review! What’s new?! So far we have used words, diagrams, numbers, the and equations to describe motion. Today we will be using graphs to describe changes in position.

7.P.1.3 Illustrate the motion of an object using a graph to show a change in position over a period of time.

What type of graph will we use? Notes Time is on the horizontal axis (x-axis) Position is on the vertical axis (y-axis) Position vs. Time graphs Position (meters) Time (seconds)

Graphing Motion Distance on the vertical axis Time on the horizontal axis Label each axis Make a scale for each axis

Graphing Motion To begin, consider a car moving in a constant motion to the right (reference direction) of 10 m/s.

Graphing Motion

Motion Graph #1: Straight, Flat Line As time passes, there is no change in position; no motion The object is “at rest”.

Motion Graph #2: Straight, Increasing Line As time passes, position changes (moving forward) The change in position is constant – no stopping & starting

Motion Graph #3: Straight, Decreasing Line As time passes, position is returning back to “start” (moving backwards) The change in position is constant (no stopping or starting)

Motion Graph #4: Changing Line A changing line means changing position Position changes (moving “forward”)  doesn’t change  position returns to start (moving backwards)

The graph below represent the motion of a car driving from home to the grocery store.

The graph below represent the motion of a car driving from home to the grocery store.

Practice Lets try it in reverse! In groups of two, assigned by your teacher, try to draw the proper position vs. time graph for the scenario given on your handout. When your group finishes, show it to the teacher, first group to get it all correct gets a prize! Remember to: 1.Label your axis and title your graph. 2.Follow the rules you learned in this lesson. 3.Keep your conversation volume at a level 1 (that is a whisper!)

Recap Exit Ticket (Make sure to write your name and the date!) Write 6 examples of a reference direction. Why do we use reference points? How did we use reference points in our graphs today? What point on your graph represents the reference point? Motion- Change in position over time Reference Point- A location to which you compare other locations. Time is on the x-axis Position is on the y-axis