-
8/14/2019 Experiment #5 PHY
1/5
Experiment #5: Work andEnergyPHY 215-03
GROUP # 4
Alia Barnes
Ramon Bing
Tiera Johnson
Date Conducted: Monday October 7th, 2013
Title Page & Format ______ (10 pointmax)
Purpose & Introduction ______ (10 point max)
Experimental Details ______ (10 point max)
Results and Discussion ______ (50 point max)
Conclusion ______ (20 point
max)
Total Grade ______
-
8/14/2019 Experiment #5 PHY
2/5
Introduction
The purpose of experiment #5 is to apply the concept of
conservation of energy to
determine the work performed by the kinetic frictional force and
use the result to determine
using energy conservation and the definition of kinetic
frictional force. The work done on an
object by a constant forceduring s displacement
is given by:
W =
(1)
Where is the constant angle between the direction of
Only the component
ofthat is along the displacement
can do work on an object. When a force is applied to an
object resting on a surface, the object will not move until the
force is greater than the maximum
force due to static friction. To keep an object moving at a
constant velocity a force must be
applied to the object equal to the kinetic frictional force. The
kinetic frictional force isdetermined by the following
relation:
(2)
Whereis the coefficient for kinetic friction and is the normal
force.
The average of the four mean force values on the force sensor
was used to calculate the height.
The symbol for the force sensor is:
(3)
The height of the incline was calculated using the
equation:sin=
(4)
Where is the angle of degrees of the incline, h(cm) is the
height of the incline, andL(cm) isthe distance traveled.
The work done by the motor to slide the block up the incline for
each heights, this certain
equation was used:
(5)
The equation used to record the blocks gravitational potential
energy change for each height was:
(6)
Where is potential energy, m is the mass,gis the gravity, and
his the height.
The equation to calculate the work done against friction for
each height is
-
8/14/2019 Experiment #5 PHY
3/5
(7)
The equation used to calculate the force of friction from the
work relationship and then
determining the coefficient of the kinetic friction was:
(8)
whereis the frictional force given by:
Experimental Details
This lab is dealing with work and how work connects force and
force together. In this particular lab the
concept of this experiment was to determine the coefficient of
kinetic friction for the moving cart using a
flat and inclined surface. Formulas were giving in order to
solve the tables of kinetic frictional force and
work of an object by a constant force during a displacement.
Every group was giving a frictional cart and a motorized cart.
The motorized cart was used to pull the
frictional cart along the tracks. We were to detect the changes
in work and energy of the objects. After
measuring the mass of the friction cart and 500 gram mass
together the Pasco force sensor was joined to
the Spark Science Interface. Using a Spark Science Interface
attached to the apparatus, the force is
measured on a graph. The Spark Science Interface was set up,
then each group was to connect the friction
cart to the motorized cart making sure the cart was pushed back
to zero and pressing the tare button
before starting. By using the Spark Science Interface data, the
force over the distance of 150 cm was
captured. At this step each group member had to intertwine
together making sure that the data was
consistent. One person would turn on the friction cart and tell
the other group member when the friction
cart was at 150 cm in order for that group member to record the
data on the Spark Science Interface
correctly
In the first table the trails of the force by the force sensor
with different inclines were recorded and
averaged.
Angle ofIncline
Trail #1Mean Force(N)
Trail #2Mean Force(N)
Trail #3Mean Force(N)
Trail #4Mean Force(N)
Forceaveraged overall four trails
(N)
0.0 1.53 1.55 1.63 1.49 1.55
5.0 1.80 1.84 1.89 1.86 1.8475
10.0 2.33 2.33 2.28 2.28 2.30515.0 2.74 2.74 2.71 2.76
2.7375
Table One: Force recorded by the force sensor
In the second table the work, coefficient of kinetic friction,
and energy was established and recorded.
Using the formulas giving and solved for.
Angle of Height Work done by Potential Work of Coefficient
of
-
8/14/2019 Experiment #5 PHY
4/5
Incline
()
(of 150 cm
mark)
motorized
cartW motor_cart
Energy
ChangePE
Friction Force
W friction
kinetic
frictionk
0.0 0 2.325 0 2.325 25.401
5.0 .1307 2.77125 .765954 2.005296 21.71
10.0 .2605 3.4575 1.5266342 1.9308 20.77
15.0 .3882 4.1065 2.275007 1.8314 19.326
Table Two: Work, Energies, and Coefficient of Kinetic Force
Results/ Discussion
Angle of
Incline()
Trial #1
Mean Force(N)
Trial #2
Mean Force(N)
Trial #3
Mean Force(N)
Trial #4
Mean Force(N)
Force averaged
over all fourtrials (N)
0.0 1.53 1.55 1.63 1.49 1.55
5.0 1.80 1.84 1.89 1.86 1.84
10.0 2.33 2.33 2.28 2.28 2.30
15.0 2.74 2.74 2.71 2.76 2.73Table One: Force recorded by the
force sensor
Angle of
Incline()
Height, h
(m)
Work done by
motorized cart(J)
Potential
Energy Change(J)
Work of
Friction Force(N)
Coefficient of
kinetic force()
0.0 0 2.32 0 2.32 25.40
5.0 .130 2.77 .765 2.00 21.71
10.0 .260 3.45 1.52 1.93 20.71
15.0 .388 4.10 2.27 1.83 19.32
Table Two: Work, Energies, and Coefficient of Kinetic Force
In order to calculate the results in Table One and Two, the mass
of the friction cart should be converted
from 598 grams to .598 kilograms. The measurements for the
length of the flat track were also converted
from 150 centimeters to 1.50 meters. Work refers to an activity
involving a force and the movement in the
direction of the force; work was completed by the motorized
cart. Energy is the capacity for completing
work; in order to do work, one must have energy.Potential energy
is the energy that is stored and
possessed by an object. The potential energy change was
calculated.Kinetic energy is associated with
motion; an object has kinetic energy due to its motion.
The work completed by the motorized cart was calculated by
multiplying the force average by 1.50
meters. The potential energy change was calculated by
multiplying the total mass of the friction cart,gravity, and the
height of each angle of incline, or shown as: . The work of
friction force was
calculated by subtracting the work of the motorized cart and the
potential energy change, or shown
as: . The results for the coefficient of kinetic force were
calculated by
. The
total mass of the friction cart was multiplied by gravity and
cosine of the angle and divided by the friction
force.
-
8/14/2019 Experiment #5 PHY
5/5
Conclusion
A frictional cart that was pulled along a track was used to
observe changes in work and energy.
Additionally, a motorized cart was used that was able to pull
the frictional cart at a constant velocity. In
order to measure the applied force, a Pasco force sensor that is
attached to a Spark Science Interface. The
experiment was a success in measuring the effect of friction on
the motion and energy of the sliding cart.The sliding cart was also
measured at different angles of the track incline. The total mass
of the friction
cart and load was measured to be .598 kilograms. With each
incline of the track at higher angles, the
mean force recorded rose with each of the four trials. After
each of the trials was completed, the force
average over all of the four trials was calculated as well. At a
zero degree angle, the average force for all
four trials was calculated to be 1.55 Newtons. Next, at a five
degree angle, the average force for all four
trials was calculated to be 1.84 Newtons. For an angle of ten
degrees, the average force for all four trials
was calculated to be 2.35 Newtons. Lastly, for an angle of
fifteen degrees, the average force for all four
trials was calculated out to be 2.73 Newtons. Table two shows
the calculated work, energies, and
coefficient of Kinetic Force. In order to calculate the height
for each of the angles, 1.50 meters was
multiplied by the function, sine and each angle degree. The work
completed by the motorized cart was
calculated by multiplying the force average by 1.50 meters. The
potential energy change was calculated
by multiplying the total mass of the friction cart, gravity, and
the height of each angle of incline. The
work of friction force was calculated by subtracting the work of
the motorized cart and the potential
energy change. The coefficient of kinetic force was able to be
calculated by dividing the mass, function of
cosine of the angle by the Friction force.
The experiment was successful in the determination of the
coefficient of kinetic force for a sliding cart on
a flat track, as well as inclined. If there were any source of
error involved in the laboratory technique, the
error woul be in computations. The Spark Science Interface was
used to calcualte the means in each trial.
In order to properly calculate the data, one had to turn the
data on and off while the cart was still moving.
If this was not done, the results would not be accurate.
References
[1] Introductory Physics II, PHY-215, Laboratory #5 Work and
Energy, Dept of Physics, Hampton
University, 2012.
