Unit 2: Motion and Force Project - Instructions

·        This project is one of the requirements for earning an A grade for this unit.
          This is an individual project to be accomplished outside of class time.
·        Design and conduct an investigation that follows the format and guidelines below.
·        Complete a typed, 3-page write-up that includes each of the elements shown.

Write-Up Format
Page 1
Title: Speed and Acceleration of a Rolling Object

Question: What are the average speed and rate of acceleration for an object rolling down an incline?

Hypothesis: Estimate what your results will be.

Materials: Rolling object (ball, toy vehicle, can, skateboard, bicycle, car, etc.)
                 Ramp, slope, hill or other inclined surface
                 Timing device (clock, stopwatch, etc.)
                 Measuring instrument (ruler, measuring tape, etc.)

Procedure: numbered steps that include the following operations:
§        Measure the distance (in meters) traveled.
§        Measure the time (in seconds).
§        Repeat your trials to insure accurate results.
§        Calculate the average speed.
§        Determine the final velocity of the object (by doubling the average speed).
§        Calculate the rate of acceleration.

Page 2
Diagram: Provide a labeled diagram or digital image of your object and inclined course.

Page 3
Data: Provide a table of your data. Label all the units.

Analysis: Show your calculations for average speed and acceleration.
                Evaluate your hypothesis.

Unit 1 Project - Example                                                                    Fred Flintstone
                                                                                                        November 1, 2008
                                                                                                        Science period 3

Speed and Acceleration of a Rolling Object

Question: What are the average speed and acceleration for an object rolling down an incline?

Hypothesis: If a car rolls down a slight incline then its motion will include the following
                    values: average speed – 3 m/s
                               acceleration – 1.5 m/s/s

Materials:  car, driveway with an inclined surface, stopwatch, tape measure

Procedure:
1.     Measure 10.0 meters from the front of the car down the driveway. Mark the 10 meter line.
2.     Have an adult sit in the car at the top of the driveway and release the parking brake.
3.     Start the stopwatch when the car begins to move.
     Stop the timer when the car reaches the 10 meter mark. Record the time in seconds.
4.     Repeat steps 2 & 3 two more times. Find the average time.
5.     Calculate the average speed of the rolling car.
6.     Estimate the final velocity of the object (by doubling the average speed.)
7.     Calculate the rate of acceleration.

Data:              trial              time in seconds 
                        1                     7.25 s
                        2                    8.30 s
                        3                    7.93 s
                     average              7.83 s

Analysis:  average speed = distance/time = 10.0 m/7.83 s = 1.28 m/s

               final velocity = 2 X average speed = 2 X 1.28 m/s = 2.56 m/s

               acceleration = final velocity – initial velocity = 2.56 m/s – 0 m/s = 0.327 m/s/s
                                      time                            7.83s

My predictions were higher than the actual results. My prediction for average speed was more than twice the actual speed. My predicted acceleration was more than four times too high.

Conclusion: When the car rolled down the inclined driveway its average speed was
                  1.28 m/s and the rate of acceleration was 0.327 m/s/s.