Falling For Gravity
PRE-LAB
You will be dropping 105 grams and measuring the acceleration. Make a prediction of the general shape of the
velocity vs. time graph.
Velocity
time
If you varied the mass that you dropped, how would the velocity vs. time graph change? Make a prediction by
drawing a new line on the graph above if the mass was raised to 205g (almost double).
If the total mass is approximately doubled, what happens to the acceleration of the falling object?
a)
b)
c)
d)
Remains unchanged.
It also doubles.
It is cut in half.
There is not enough information to make this prediction.
Draw a vector diagram of an object in free fall showing only velocity vector(s)
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MATERIALS
1 Mass and hanger set
timer tape
1 spark timer
adhesive tape
PROCEDURE
Set up the spark timer as pictured below. It is important that the spark timer is completely vertical to minimize the
friction between the spark timer and the tape.
1. Using the spark timer set at 60 Hz and a 100-gram mass on the hanger, attach a piece of timer
tape that is at least 1 meter in length.
2. Drop the hanging weight so that it pulls the timer tape through with as little friction as possible.
3. Using the spark timer data, calculate the acceleration of the free falling object. Use the data
table on the next page to help with your measurements.
4. Add an extra 100 grams to the hanging mass and repeat the same measurements and calculate
the acceleration.
5. Add an additional 100 grams to the hanging mass and repeat the same measurements and
calculate the acceleration.
6. Record your acceleration data on the group data table on the board.
7. Number each time interval (dot-to-dot) of your ticker tape starting from the first dot. Now
carefully cut the tape intervals. Each interval represents the distance the object moves during that
interval of time. Tape them on a distance versus time graph, d-t.
7. Using your calculated data for velocity, create a Velocity versus time graph, v-t.
8. Using your calculated data for acceleration, create an Acceleration versus time graph, a-t.
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DATA
105 grams
Interval
1
Interval
2
Interval
3
Interval
4
Interval
5
Interval
6
Interval
7
Interval
8
Interval
9
Calculations
Acceleration
Interval
1
Interval
2
Interval
3
Interval
4
Interval
5
Interval
6
Interval
7
Interval
8
Interval
9
Calculations
Acceleration
Interval
1
Interval
2
Interval
3
Interval
4
Interval
5
Interval
6
Interval
7
Interval
8
Interval
9
Calculations
Acceleration
Time
Interval
Length
Velocity
205 grams
Time
Interval
Length
Velocity
305 grams
Time
Interval
Length
Velocity
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Questions:
1. How does your velocity data for the 105g, 205g, and 305g mass compare to your
predicted velocity graph?
2. What can you conclude about the effect of the mass on the acceleration?
3. What is the significance or the slope of the v-t graph? Calculate the slope and show
your work.
4. How does your answer compare to your calculated value in the data table?
5. On your v-t graph, choose two times (Using t=0 for 1 will make it easier). Shade the area
between those times and below the velocity line. Now, calculate this area. Show work
and answer.
6. What is the significance of the area below the v-t graph? How does your answer from the above
question compare with our d-t graph for the same time interval? Explain.
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