Niki&Maddyfreefalllab

Free Falling Lab group members: Niki and Maddy Due: 9/30/10

Objective: What is the acceleration of a falling body?

Materials: Ticker tape timer, timer tape, masking tape, mass, clamp, meterstick

Hypothesis: When dropping the weight acceleration will be at zero at the time of release and accelerate at a rate of 9.81 m/s^2 as it falls to the ground because 9.81 m/s^2 is the acceleration caused by gravity.

Procedure:
 * 1) Make sure the tick tape timer is set to 60 hz.
 * 2) Clamp the tick tape timer to the top of a closet door.
 * 3) Put the ticker tape through the time while it is off
 * 4) Attach the mass using masking tape to the end of the ticker tape
 * 5) Turn the tick tape timer on and drop the mass
 * 6) Measure the distance of each dot made by the tick timer (each dot’s distance from the initial dot)

Dot number 0/60= time(s)

1. Does the shape of your graph agree with the expected graph? Why or why not? a. Yes it does because it continues to accelerate as time passes due to gravity because the object is falling. It starts at the point (0,0) which is an acceptable y-intercept because at 0 seconds, the distance is 0.

2. How do your results compare to that of the class? (Use Percent difference to discuss quantitatively.)

3. Did the object accelerate uniformly? How do you know? a. Because gravity is a constant number (9.8 m/s^2), it is falling uniformly throughout the entire lab.

4. What should the velocity-time graph of this object look like? a. This graph should be a linear line with a positive slope. Because at 0 seconds it is at position 0, the y-intercept should also be 0,0. Because the slope of the velocity-time graph, the line on an acceleration-time graph would be a horizontal line. This is due to the fact that gravity is a constant acceleration.

5. Write down the expected equation of the line from this v-t graph (use specific information from your x-t graph). didn't need to do this, only use value you got for 'g' as slope and set y-int =0. Your slope here is the velocity in the middle of that .5 and .6 interval. You need a second velocity at a different point. THEN you can find a.

6. What factor(s) would cause acceleration due to gravity to be higher than it should be? Lower than it should be? a. If we calculated the acceleration incorrectly incorrect calcs are not valid sources of experimental error it may cause the acceleration to be greater than it truly is. Also if air or another force was also pushing down on the mass while it was falling it would cause the acceleration to be greater. It may also be greater if the object was thrown down rather than dropped because it would cause a greater initial velocity and a greater acceleration. b. Attaching something parachute-like would cause the acceleration to be lower than gravity because it would be working against the force of gravity. If there was also a force acting on the object that was in opposition to gravity then the acceleration would be less. specifically, what force?

Conclusion: Our lab was successful because our rate of acceleration was close to the gravity. Gravity is 9.81 m/s^2 and our results were 898.32 cm/s^2. Our percent error was only about 8 percent.

Error: We let the tape flow freely through the tick tape timer however if we didn’t that would slow the acceleration. We could have had errors in recording the data however our graph had an R^2 value of 1 so our measuring was not very off. Friction was the major source of error. The friction slows down the acceleration of the mass. Even though we did not add friction by threading the tape through our fingers as it fell the tape still had to go over the door and through the tick tape timer itself. All these things caused friction, which caused the rate of acceleration to be slower.

Implications: We have all heard of that if you drop a penny off the empire state building it could be lethal. When you are younger it doesn’t really make sense that a penny could do any damage. When you learn how the rate of gravity would cause the penny to have a high velocity at the time of impact it becomes much more clear why a penny falling from a building could actually do a lot of damage. great application! Please don't use headings on the three sections... it should flow in an essay-like manner.