## The Mystery of the Accelerating Race Car

### Johnny WolfeSanta Rosa District Schools

#### Description

Acceleration is the rate at which speed is changing with respect to time. Students learn how to compute acceleration (a) by dividing the change in speed by the time (t) needed to make the change.

#### Objectives

Understands concrete and symbolic representations of real and complex numbers in real-world situations.

#### Materials

-Accelerating Race Car Examples (See Associated File)
-Accelerating Race Car Worksheet (See Associated File)
-Accelerating Race Car Checklist (See Associated File)

#### Preparations

1. Prepare transparencies (if teacher uses overhead for examples).
2. Have marking pens available for overhead.
3. Have the Accelerating Race Car Examples prepared and ready to demonstrate to students. (See Associated File)
4. Have copies of the Accelerating Race Car Worksheet for each student. (See Associated File)
5. Have copies of the Accelerating Race Car Checklist for each student. (See Associated File)

#### Procedures

Note: This lesson does not cover percents and scientific notation.

Prior Knowledge: Students should be familiar with basic operation skills such as addition, subtraction, multiplication, division, exponents, fractions, decimals, solving formulas and working with units.

1. Get students' attention by making the statement, “We are going to study the mystery of the accelerating race car--what determines its acceleration and the parts needed to complete this investigation.”

2. Ask the students if they have ever been in an automobile when someone “stomps” the gas pedal suddenly. Have the students explain the effects on their bodies. Explain that this is “acceleration.”

3. Make the following statement, “Acceleration is the rate at which speed is changing with respect to time. To compute acceleration (a) you divide the change in speed by the time (t) needed to make the change. The change in speed is the difference between the final speed (f) and the starting speed (s). This can be summarized by the following formula: a = (f – s)/t.

4. Work example #1 from the Accelerating Race Car Examples. (See Associated File)

5. Ask the students if they have ever been in an automobile when someone “stomps” the brake pedal suddenly. Have the students explain the effects on their body. Explain that this is “de-acceleration.”

6. Work example #2 from the Accelerating Race Car Examples. (See Associated File)

7. Explain that the units are placed into the formula and remain in the formula. This describes the effects of motion in relation to time.

8. Distribute the Accelerating Race Car Worksheet. (See Associated File)

9. Instruct the students to correctly replace the variables in the acceleration formula with the correct values from the verbal description. Students should show their work and record results on the worksheet.

10. Next the students evaluate the acceleration formula correctly, show their work, and place the result on the worksheet.

11. Distribute the Accelerating Race Car Checklist (See Associated File) and describe what constitutes an A, B, C, D, and F in the Checklist.

12. As the students work, move from student to student, observing their work and lending assistance.

13. Collect and score students' worksheets. (See Accelerating Race Car Worksheet Key and Accelerating Race Car Checklist) If students have had sufficient practice to warrant a grade, grades may be posted in the grade book. If not, work should be formatively assessed.

14. Students with grades below C should be remediated.

#### Assessments

Use the Accelerating Race Car Worksheet Key and the Accelerating Race Car Checklist to score students' worksheets. (See Associated File) Grades are assigned for the worksheet and recorded in the grade book if students have had sufficient practice and feedback opportunities. If not, students should be formatively assessed until they have had enough practice and feedback to show mastery of the subject. Students who receive a grade below C should be remediated.

#### Extensions

Ask students to pick a starting and finishing speed. Then vary only the time to see how this affects the acceleration.