Do Now for 4/15/13 Open Books up to activity E75 HW: None E75: Interpreting Motion Graphs • Today’s Target: I will be able to see how a graph can be used to describe the motion of an object. • Binder clean out and grade evaluation • Introduce and write up E75 • Complete procedure • Clean up • Analysis? Binder Clean Out • Keep: – General Information – Vocabulary – E Unit Materials • Complete grade evaluation sheet – Did you earn extra credit??? E75: Interpreting Motion Graphs • We measured the speed of carts in activity 74. • Were the carts always traveling at the same speed? • Do you travel at the same speed for your entire trip to school? • Do you always travel in the same direction in your trip to school? • We can use a graph to visualize the trip of someone traveling to and from school. E75: Interpreting Motion Graphs • Where is the length of time located? Where is distance traveled located? What do you think this part of the graph means? What do you think this part of the graph means? What do you think this part of the graph means? One square per person. Do Now for 4/16/13 • Take out E75 • HW: Expanded answer for question #2 due TOMORROW!! • Today’s Target: I will be able to see how a graph can be used to describe the motion of an object. • Complete graphing data – Make sure you include reasons why you put the strips where you did! • Go over data • Analysis 1 through 5 • Key Points • Expanded answer for #2 E75: Interpreting Motion Graphs • 1. Identify a place on each graph where the slope of the line changes. What does a change in the slope of a motion graph indicate? – A change in slope indicates a change in the distance traveled in a given time, which is defined as speed. E75: Interpreting Motion Graphs • 2. Which student –Teasha or Josh– started out faster? Explain how you know this. • Expanded Answer – Correctly state who started out faster. – Give at least two (2) pieces of evidence from the graph to support your answer. – Due tomorrow. E75: Interpreting Motion Graphs • 3. How far into the trip did Josh turn around? Describe what the graph looks like at this point in the trip. – Josh turned around 6 minutes after he left home—5 minutes traveling 2 miles and 1 minute stopped. You know this because from Minute 6 to Minute 10, the slope of the graph is negative(downward), which indicates a reversal in the direction of motion. With a positive (upward) slope, the distance away from the starting point increases with time. With a negative slope, distance from the starting point decreases with time, which means that the car is getting closer, or traveling back toward, the starting position. E75: Interpreting Motion Graphs • 4. Look at the motion graphs shown on page E-14. Match the descriptions here to the correct graphs: • a. A car moving at a constant speed stops and then moves in the opposite direction at the same speed. – Graph 2 • b. A car moving at a constant speed stops and then moves faster in the same direction. – Graph 4 • c. A car moving at a constant speed changes to a higher constant speed. – Graph 1 • d. A car moving at a constant speed changes to a lower constant speed. – Graph 3 E75: Interpreting Motion Graphs • 5. A car that accelerates (ak-SELL-ur-ates) is one that speeds up, slows down, or changes direction. Which graph on page E-15 shows a car continually accelerating? Explain how the shape of the graph shape shows this. – Graph A (on the left) shows an object accelerating. This is because it has a curved line that shows increasing steepness in slope as time increases. Graph B (on the right), in contrast, has a constant slope so it shows constant speed. Both graphs show motion in a straight line. E75: Interpreting Motion Graphs – Key Points • 1. The motion of an object can be describe by its position, direction of motion, and speed. • 2. Motion can be measured and represented on a graph. • 3. Average speed is the distance an object travels divided by the time taken to travel that distance. • 4. Mathematics is important in all aspects of scientific inquiry. E75: Interpreting Motion Graphs • 2. Which student –Teasha or Josh– started out faster? Explain how you know this. – Teasha started out faster. This can be determined several ways: – 1) The trip strip for Teasha’s first segment states that the car traveled 3 miles in 6 minutes. Using the formula s = d/t, this is a speed of 0.5 miles/minute. The trip strip for Josh’s first segment states that the car traveled 2 miles in the first 5 minutes. Using the formula s = d/t, this is a speed of 0.4 miles/minute. – 2) The trip strip for Teasha’s first segment states that the car traveled 3 miles in 6 minutes. Since Josh did not travel as far in the same amount of time, Tesha must have been traveling faster. – 3) The first segment of Teasha’s graph has a steeper slope than the first segment of Josh’s graph. A steeper line (higher value for slope) indicates a higher speed.