# Engineering Physics — Lab Report Sample - PDF

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```					                Engineering Physics — Lab Report Sample
OCCC

1     Purpose
Perhaps you’re trying to verify the conservation of energy or momentum, or maybe ﬁnding the value
of some fundamental constant like e /m or g . This is the appropriate place to state the purpose of the
experiment, and a couple/few sentences of background theory on what these quantities are and why this
is important to do.

2     Procedure
List, in a narrative (paragraph, complete sentences) format, what you did to take your data (not calcu-
late your results). Pretend you’re addressing a reasonably bright colleague who may not be familiar with
the principles we’re studying in this class, but who intends to duplicate the experiment based upon your
report. Please include special techniques used and any difﬁculties encountered.

3     Results
3.1   Energy calculations

Force vs. Displacement (Pendulum)
4

3.5

Mass (g)    Displacement (cm)                               3

50                      6                            2.5

100                     14
Force (N)

2
150                     21
200                     31                            1.5
250                     39
300                     41                             1                                          Observed
slope=6.87 N/m
350                     52
0.5
400                     58
0
0      0.1      0.2            0.3               0.4   0.5   0.6
Displacement (m)

Figure 1: Plot of made-up important data

Here, show (or point to an appendix containing) the results of your calculations of relevant quantities,
like:
W is most easily calculated from the area under the force vs. displacement curve (Fig. 1). Since the
data is linear, we can just compute the area of the triangle

1                1
W = (base)(height) = (0.58 m)(3.96 N) = 1.15 J
2                2

1
...and so on. If a plot is included, you should discuss its relevance and how you are inferring results
from it. Make sure you’re following the guidelines for a good graph, since the craft of making good, clear
scientiﬁc plots is extremely important. If you are applying the same calculation to many data points, just
show an example of the process for one point so someone unfamiliar with the experiment can follow what
you’re doing (and can re-create the plot if they want to):

1       1
K = m v 2 = (1.154 kg)(1.4 m/s)2 = 1.13 J
2       2
U = m g h = (1.154 kg)(9.81 m/s2 )(0.11 m) = 1.24 J

3.2   Error Estimates
In this section, calculate the MAE expected in your results, like so:
In general, the maximum accountable error in measuring a propagated quantity Q = C x m y n is

∆Q    ∆x    ∆y
=m    +n
Q     x     y
Here,

Measurement            Least count (∆x )
Displacement (m)                     0.001
Mass (kg)                            0.001
Time (s)                             0.001

so for the Kinetic Energy K ,
2
1     1           ∆s
K = mv2 = m
2     2           ∆t

∆K   ∆m b    ∆s ∆t                 0.001    0.001 0.001
⇒      =      +2    +              =         +2      +          = 4.9%
K    mb      s   t                1.145     0.1   0.072
Results for the 3 energy measurements are then

Measurement               Energy
W                   1.16 ± 0.003 J
U                   1.24 ± 0.013 J
K                   1.13 ± 0.054 J

4     Conclusions
brieﬂy, your ﬁnal calculations and the relevance to the initial purpose of the experiment. Your conclusion,
even if it is not what you expected to ﬁnd initially, should be supported by the data and the uncertainty.
Comment on the errors in the experiment, and if your initial purpose was not met, also trace the probable
cause of disagreement. Note that errors in measurement should already be taken care of in the MAE
calculation.

2

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