Acceleration is defined as the rate of change
of velocity with respect to time. It is measured in SI units by meter/second2.
One common unit of acceleration is known as g, the acceleration due to gravity
of the Earth. An accelerometer is an instrument used to measure acceleration
and the effects due to gravity.
Materials Used:
low-g accelerometer
LabPro
laptop
masking tape
Experiment 1
In this experiment we rode the elevator at Midwood
High School and using an accelerometer that was connected to the laptop through
the LabPro.We zeroed the accelerometer and let the Logger Pro software collect
the acceleration of the elevator. It collected the elevator's acceleration
at 0.1 second intervals for a total of 20 seconds. In this experiment we started
collecting the data on the 3rd floor as the elevator travelled down to a stop
in the basement. The results are compiled in this table.
The acceleration vs. time graph shows that the peak acceleration
of 0.64 m/s2 was reached at 1.9 s, dropped to 0 m/s2 while the elevator was traveling at a constant speed, and decelerated
to 0.71 m/s2 at 18.9 s until the elevator came to a rest.
We applied the integral function to the acceleration graph to
graph the velocity vs. time graph.
The velocity vs. time graph shows that the elevator started
from rest and accelerated in the downward position reaching a peak
speed of 0.820 m/s at 6.1 s, until it reached a constant velocity. When we reached the
basement the graph shows that the elevator decelerated and came to
a stop.
We again applied the integral function to the velocity graph
to graph the displcement vs. time graph.
The displacement vs. time graph shows that the elevator started
from rest and accelerated in the downward position a distance of
14.309 m, the distance from the 3rd floor to the basement of Midwood
High School.
Experiment 2
In this experiment we rode the elevator at
Midwood High School, but instead of going down, we decided to go up.We zeroed
the accelerometer and let the Logger Pro software collect the acceleration
of the elevator. It collected the elevator's acceleration at 0.1 second
intervals for a total of 20 seconds. In this experiment we started collecting
the data on the 2nd floor as the elevator travelled up to a stop at the
4th floor. The results are compiled in this table.
The acceleration vs. time graph shows that the elevator decelerated from
rest to 0.66 m/s2, then did not accelerate until it reached a peak acceleration
of 0.74 m/s2.
When we graphed the velocity, the graph showed that speed increased, reached
a constant value for a few seconds, then increased and kept increasing
even
when the elevator stopped. Therefore, we adjusted our speed values
by utilizing the function
"velocity"-0.06886-0.01138*"Time"
Using
our adjusted velocity values, we produced a new graph which showed
that the speed increased, remained constant and then dropped to zero
when the
elevator came to a rest.
The distance vs. time graph derived from utilizing the integral function
for our adjusted velocity graph showed that the total displacement the
elevator
travelled was 8.176 m, about two floors of our school building.
Olga Strachna, Diana Kuruvilla, Dorothy Soo -- 2005
