Introduction: An object is said to be freely falling if only the gravitational force acts on it and there are no other forces. Normally, as objects fall, they experience fluid friction (an example of a fluid friction would be the resistance felt as an object traveled through air or water). Only in a vacuum can you really be in free fall. However, for certain objects, the fluid friction is so small, you can neglect it. | Part I:

Remember, d=v_ot+ 1/2at² is the equation for the distance an accelerating object travels. How could you simplify that equation if you are starting from rest?

For the manual lab, you will need to find a place where you can drop an object several meters to the ground without breaking anything. A small press-and-seal bag (e.g., Ziploc) of sand or rice tucked in a sock will work as a mass if you need something that will not bounce. You must be able to time the release and the landing accurately. You will also need to accurately measure the distance.

Materials: Calculator, stopwatch, meter stick, droppable object

If you need assistance collecting the data, ask a friend or family member.

1. Using the meter stick, measure two different heights that you can drop an object from. This object should be massive enough so that air resistance can be minimal (such as a book, ball, etc.)
2. When you are ready, record the amount of time it takes for the object to hit the ground.
3. Using the data, determine the acceleration due to gravitational force. Be sure to show your work for all the calculations.
4. What to submit:
   1. Your data collected, clearly organized.

	Distance (meters)	Time (seconds)	Acceleration due to Gravity (m/s2) (show your work in part b, below)
Trial 1
Trial 2

1. Your calculations for acceleration due to gravitational force (Hint :Remember, d=v_ot+ 1/2at² is the equation for the distance an accelerating object travels. How could you simplify that equation if you are starting from rest?). Make sure to show your work below.

1. A description of the various sources of error when conducting this activity.

Part II:

Trial 1:

1. Get a book and put a sheet of paper on top of it. Fold the paper as needed to keep the paper from sticking over the edge of the book.
2. Hold the textbook with the paper on top, horizontally about waist high.
3. Drop the book and paper so that they hit the floor flat.
4. Record your observations.

Trial 2:

1. Take the same book in one hand and the paper in the other.
2. Hold the book and paper at the same height.
3. Drop the book and paper simultaneously.
4. Record your observations.

Before you begin Trial 3, think about your observations from trials 1 and 2. What did you observe to occur differently between the two? Writee a paragraph (complete sentences) explaining the difference between Trial 1 and Trial 2 observations.

Trial 3:

1. Form a hypothesis of what you think would happen differently if you took the flat piece of paper and the book that you used before and compared each to another piece of paper that iscrumpled up tightly into a ball? Record that hypothesis below.

1. Test your hypotheses by dropping the flat sheet and the crumpled sheet at the same time.
2. Now, drop the book and the crumbled paper.
3. Record your observations.