Investigating the Motion of a Falling Body

Aim

To measure the position and time during motion and to use that data to plot a “Position vs Time” and “Velocity vs Time” graph from which we can calculate the magnitude for gravitational acceleration, \(\vec{g}\).

Method

1. Work with a friend. Copy the table below into your workbook.

2. Clamp the timer to the table to allow the tape to fall through the staples on the timer such that the ticker tape will be perpendicular to the floor. Plug in the timer.
3. Thread a piece of ticker tape through the staples. Make sure the tape is under the carbon disc. The length of the tape should be the distance from the timer to the floor.
4. Using masking tape attach a 100 g mass to the end of the tape closest to the floor.
5. Position the foam cushion directly below the mass. (The cushion will protect your masses and your floor)
6. Hold the tape so that it is vertical and will easily pass through the staples.
7. Turn on the timer.
8. Let go of the tape with the mass, allowing it to drop to the floor.
9. Turn off the timer.
10. Repeat.
11. Take each tape and find the first clear dot nearest the mass end of the tape. Circle this first clear dot and label it as zero. Then count five dots and label the fifth dot as number 1. Count another 5 dots and label the fifth dot number 2. Continue this procedure.

12. On each piece of tape, measure the distance between successive dots. Note these distances in the table below.

13. Use the frequency of the ticker timer to work out the time intervals between successive dots. Note these times in the table below.

14. Work out the average of the two distance values between successive numbered dots.

15. The time interval between two dots is 0,02 s so the time between numbered dots is 0,1 s.
16. Use the average distance between numbered dots and the known time interval to calculate velocity.

17. Use the magnitude of the velocity and time values to plot a graph of “Velocity vs Time” onto graph paper. Stick the graph paper into your workbook.

18. Draw the best straight line through your data points.

19. Determine the slope of the straight line. This is the magnitude of the acceleration.

Results

Discussion

Describe the motion of the mass using the graphs.