L2.2 Speed, Velocity and Acceleration PDF

Unit 2: Forces and Motion Lesson 2: Speed, Velocity, and Acceleration YOSRA SAAD 1 Objectives Students will determine the average speed of an object: From calculations. Using distance-versus-time graphs. Students will use text evidence to compare v...

Unit 2: Forces and Motion Lesson 2: Speed, Velocity, and Acceleration YOSRA SAAD 1 Objectives Students will determine the average speed of an object: From calculations. Using distance-versus-time graphs. Students will use text evidence to compare velocity, speed, and acceleration. Students will interpret graphs to determine acceleration. YOSRA SAAD 2 Guiding Questions How do you determine speed from calculations and distance-versus- time graphs? How is velocity related to speed and acceleration? How can you interpret graphs to determine acceleration? YOSRA SAAD 3 Vocabulary Speed Slope Velocity Acceleration Average variable YOSRA SAAD 4 Connect It! YOSRA SAAD 5 Calculating Speed Speed is the distance an object moves per unit of time. It is a type of rate A rate tells you the amount of something that occurs or changes in one unit of time. YOSRA SAAD 6 Calculating Speed YOSRA SAAD 7 Example Problems Example 1 Example 2 A car travels 50 m in 20 s; What A ball rolled at a speed of 3 m/s is its speed? for 2.5 s; how far did it travel? YOSRA SAAD 8 Example Problems Example 3 Example 4 How much time will it take you An airplane on a runway can to travel a distance of 150 m at cover 500 m in 10 s; what is the a speed of 30 m/s? airplane’s average speed? YOSRA SAAD 9 Instantaneous and Average Speeds Average speed: it can be found by dividing the total distance travelled by an object by the total time. It cannot tell us the speed at every moment in time. YOSRA SAAD 10 Instantaneous and Average Speeds Instantaneous speed: the speed at a particular instant in time. YOSRA SAAD 11 Average Speed A racecar at the Daytona 500 zips around the track. It travels the first 80 kilometers in 0.4 hours. The next 114 kilometers take 0.6 hours. The following 80 kilometers take 0.4 hours. Calculate the racecar’s average speed. YOSRA SAAD 12 Calculating Speed from Distance-Time Graphs Example: A lab cart moves on a horizontal table top. The traveled distance and time are measured by the motion sensors. First, we'll make a table from our observations. YOSRA SAAD 13 Calculating Speed from Distance-Time Graphs Points are not connected in a scatter plot. This is how a scatter plot differs from a line graph. YOSRA SAAD 14 Calculating Speed from Distance-Time Graphs A line of best fit, or trend line, can help us predict outcomes using the data that you already have. It is drawn on a scatter plot that best fits the data points. YOSRA SAAD 15 Calculating Speed from Distance-Time Graphs This graph shows the distance versus time for an object. Speed is the slope of the best fit line on a distance versus time graph. YOSRA SAAD 16 YOSRA SAAD 17 Describing Velocity Velocity is the speed at which an object travels in a given direction. It includes both speed and direction of motion. It is a vector. YOSRA SAAD 18 Determining Acceleration Acceleration is the rate at which velocity changes. A change in velocity can involve a change in speed, direction, or both. In science, when an object accelerates, it increases speed, decreases speed, or changes direction. YOSRA SAAD 19 Calculating Acceleration YOSRA SAAD 20 YOSRA SAAD 21 YOSRA SAAD 22 YOSRA SAAD 23 Graphing Acceleration Graphing Acceleration – Book Activity Worksheet YOSRA SAAD 24 Lesson 2 Check What three changes in motion show that an object is accelerating? What is the average speed of a train that covers 80 km in 1 h, 200 km in 2 h, and 420 km in 4 h? A ball is pushed from a stop and rolls 6 m in 2 s. Student A says the average speed of the ball is 3 m/s. Student B says the average speed of the ball is 1.5 m/s2. Which student is correct? Explain your answer. YOSRA SAAD 25 Lesson 2 Check A student graphed distance versus time for an object that moves 14 m every 2 s. What is the slope of the line on the graph? Explain. If the line on a distance-versus-time graph and the line on a speed- versus-time graph are both straight lines going through the origin, can the two graphs be displaying the motion of the same object? Explain. YOSRA SAAD 26