AVERAGE SPEED LAB

Science Standards : b. Students know that average speed is the total distance traveled divided by the total time elapsed and that the speed of an object along the path traveled can vary. c. Students know how to solve problems involving distance, time, and average speed. f. Students know how to interpret graphs of position versus time and graphs of speed versus time for motion in a single direction. Problem: What is the average speed of an object rolled down a ramp?

Materials: small object or ball, tape, stopwatch, metal rods or board, rubber bands, textbook, smooth area of floor, meter stick Procedure: 1. Rubber band the 2 metal rods together or use a board. 2. Lay the book on the floor/counter in a place where you have 2.5 meters of distance to work. 3. Slant the rods or board by resting one end on the top of the textbook. 4. Use the tape to mark off distances along the floor for 0.0m, 0.5m, 1.0m, 1.5m and 2.0m starting from the bottom of the rods. 5. Place the ball or small object at the top of the rods and release it as a practice run. Make sure the object will roll the full 2.0 meters at a slow enough speed for you to time with the stopwatch. Adjust the release point of the ball as necessary for good data collection. Mark the release point with tape on the board so that every roll starts in the same place. 6. Release the object and start timing when the object reaches the 0.0m mark at the bottom of the board. Measure the time it takes for the object to travel 0.5m. Record the time in your table. 7. Repeat step 7 for each of the other measurements. (1.0m, 1.5m and 2.0m) 8. Repeat this process for a total of 3 trials. 9. Calculate average speed using Average speed = total distance/ total time or V=d/t Record in your data table. Include correct units and significant figures.

Data: Object______Distance in meters Time in seconds (s) (m) Trial 1 Trial 2 Trial 3 Avg. time 0.0 m 0.5 m 1.0 m 1.5 m 2.0 m Average speed m/s

Questions:. 1. Using your data, make a line graph showing distance on the independent variable axis and time on the dependent variable axis. Refer to your book for examples of motion graphs. Follow all rules for graphing. Include a key to show the data for each trial and the average. 2. Is the speed of the object constant over the whole 2.0 meters? Use information from your graph to support your answer. Were there any factors that may have affected your data? For, example, did you release the ball from the same starting point each time? Make a list of possible sources of error in this experiment. 3. World record holder Usain Bolt runs the 100m in 9.58 sec and the 200 m in 19.19 sec. What is his speed in each event? What is his speed in mi/hr? (Hint: multiple your answers by 2.2). 4. Major league pitcher Nolan Ryan was officially clocked throwing a fastball 100.9 mi/hr. How fast is this in m/s? Conclusion: