Physics 1020
Laboratory #3 Acceleration of Falling Objects
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Acceleration of Falling Objects
Freely falling objects are those whose motion is only under the
influence of gravity. When up is taken as the positive direction,
objects fall with a constant downward acceleration a of
a y   g  9.81 m/s 2 .
The motion of objects in free-fall obeys the kinematics equations
governing one-dimensional motion, but with the acceleration always
equal to the above constant.
The displacement in the y-direction is given by
y  yo  vo y t  1 2 a y t 2
where y and yo are the final and initial positions in the y-direction, vo is
the initial velocity in the y-direction and t is the time.
The instantaneous velocity, vy, may be found as the slope of the
tangent to a displacement versus time graph at any point. In relation
to other kinematics variables, instantaneous velocity is given by
v y  vo y  gt .
Plotting one kinematics variable versus another allows you to see
these relationships, as well as to find constants such as the
acceleration due to gravity and initial velocity.
Physics 1020
Laboratory #3 Acceleration of Falling Objects
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Interpreting Graphical Results:
To draw physical meaning from graphical results, it is necessary to
compare the physics equations relating the plotted variables to the fit
results.
As given on the previous page, the vertical displacement of an object
in free fall is given by
y  y o  vo t  1 2 a y t 2
which may be rewritten as
y   1 2 gt 2  vo y t  yo
A plot of y vs t will be fit to a quadratic form:
y  at 2  bt  c .
The coefficients in each of the two forms must be compared to
determine which physical quantity is represented by a, b and c.

Similarly, velocity of an object is given by
v y  vo y  gt
which is rearranged to give
v y   gt  vo y .
A plot of v vs t will be fit to the linear form
v  mt  b.
Comparing the two equations indicates the physical meaning of the
parameters m and b.

Physics 1020
Laboratory #3 Acceleration of Falling Objects
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Prelab Questions
These questions need to be completed before entering the lab. Please show all
workings.
Marker’s
Initials
Prelab 1
complete
incomplete
For a falling ball, which bounces, draw the expected shape of the vertical position
vs. time graph.
Prelab 2
From the position vs. time graph of an object moving with constant acceleration,
how could you find the velocity?
STAPLE YOUR PRE-LAB TO THIS PAGE
Physics 1020
Laboratory #3 Acceleration of Falling Objects
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Name and Student Number:
___________________________________
Date:
___________________________________
Partner:
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CHECKPOINT:
Have an instructor check your graphs and initial.
QUESTION 1:
QUESTION 2:
𝑡1 =
𝑡2 =
QUESTION 3:
𝑥(𝑡1 ) =
𝑣(𝑡1 ) =
QUESTION 4:
𝑣max 𝑢𝑝 =
STAPLE YOUR GRAPHS TO THIS PAGE
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Physics 1020
Laboratory #3 Acceleration of Falling Objects
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QUESTION 5:
𝑣max 𝑑𝑜𝑤𝑛 =
QUESTION 6:
QUESTION 7:
TABLE 1:
value
Expected value of a
(see instructions)
Automatic Fit parameter A
uncertainty
N/A
units
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Physics 1020
Laboratory #3 Acceleration of Falling Objects
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QUESTION 8:
TABLE 2:
Value
Slope
QUESTION 9:
Uncertainty
Units
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Physics 1020
Laboratory #3 Acceleration of Falling Objects
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TABLE 3:
Mean
Standard
Deviation
Samples
Acceleration
QUESTION 10:
𝒈=
QUESTION 11:
QUESTION 12:
Staple graph(s) to the
reverse side of this page.
Standard
Error