Essay Color Key

Free Essays
Unrated Essays
Better Essays
Stronger Essays
Powerful Essays
Term Papers
Research Papers





Trolley Investigation

Rate This Paper:

Length: 1738 words (5 double-spaced pages)
Rating: Red (FREE)      
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Trolley Investigation

Choosing a Variable

Before I begin the investigation, I must first decide which variable I
should investigate.

Variables can be divided into 2 major groups: dependant variables and
independent variables. In measuring the behaviour of a trolley the
dependant variable is speed. This is because the speed will change
when other variables are changed.

An independent variable is a variable which cannot be affected by
other variables. There are many independent variables in measuring the
behaviour of a trolley and I must first assess which one would be a
suitable one to investigate:

* Shape of the trolley- the shape and aerodynamics of the trolley
can affect its motion behaviour. This is because the trolley is
affected by air resistance and certain shapes are more air
resistant than others. This would be a difficult variable to
investigate because we would be limited by the number of shapes we
could use. It would be difficult to plot the results in the form
of a line graph.

* Gradient of ramp- gradient of the ramp affects the motion of the
trolley because as the gradient gets larger the height the trolley
starts from gets higher as well. This would mean that at higher
points the trolley would have more gravitational potential energy.
This would be a good variable to investigate because we can use
various gradients but it might be slightly difficult to measure
some angles with the protractor.

* Height of start position- this affects the motion of the trolley
because as the height gets larger the trolley gains more
gravitational energy. This would be a good variable to investigate
because there are many heights we can use and it is also easy to
calculate the gravitational potential energy of the trolley given
the height.

* Mass of the trolley- this affects the motion of the trolley
because acceleration is equal to force over mass and the force
(gravity) remains constant so as mass increases, so would the
acceleration and therefore the speed of the trolley at the bottom
of the ramp increases as well. This would be slightly difficult to
investigate because we may be limited by the weights we can use.

I will investigate how the height of start position affects the speed
of the trolley because it is extremely simple to measure the height
and it is also easy to calculate the amount of gravitational potential
energy of the trolley given the height.

Aim

I will investigate the relationship between the height a raised to on
a ramp and the speed of it at the bottom of the ramp.

Apparatus

Metre Rule- this will be used to measure the length of the ramp and
the height from which the trolley is released.

Trolley- this is what we will be investigating the behaviour of. We
will raise it to a certain height on the ramp and then release. We
will then measure the speed of it at the bottom.

Ramp- this is really a long, straight plank of wood. The trolley will
travel along this.

Jack- this is the device which will be used to raise the ramp to
certain heights.

Light gate- this will be used to measure the speed of the trolley at
the bottom of the ramp. It measures the speed in m/s to 3 decimal
places.

Diagram

[IMAGE]

Method

The apparatus will be set up as above. The jack will be used to raise
the ramp to a certain height. The height of the start position of the
trolley will be measured and then the height of the end position of
the trolley would be measured using metre rulers and the difference of
these two measurements would give the height, h. The light gate would
also be connected to the QED and positioned at the end position of the
trolley. The trolley would be raised to the top of the ramp. It will
then be released down the ramp without any human force pushing it
down. The light gate would measure the time interval for the trolley
to pass through the light gate at the bottom of the ramp. For each
height the time interval for the trolley to pass through the light
gate will be measured 3 times. This will then be repeated with a
number of different heights.

Measuring Variables

Height of ramp- this will be measured using a ruler. Each height will
be measured to the nearest millimetre.

Time Interval of trolley- this will be measured using a light gate as
opposed to a ticker timer or by using a stopwatch because it is much
more hi-tech and effective and also takes out the factor of human
error from the results. It measures the speed in seconds to 3 decimal
places.

Precautions

For each height, 3 different speed measurements will be taken and then
the average would be calculated. This would make the results more
reliable because it is easy to isolate any anomalies. This would also
ensure that the results are reliable because we are reproducing
similar results.

Each height will be measured to the nearest mm using the metre rule.
It would be measured three different times just to check that it is at
the correct height.

Prediction

I predict that as the height increases so will the speed of the
trolley.

When released from the top of the trolley, gravitational potential
energy transfers to kinetic energy. Assuming that no energy is lost by
friction:

[IMAGE]

This rearranges to:

v² = 2gh


The force, g, is always constant and h is the independent variable and
v² is the dependent variable.

Therefore h will be directly proportional to v² and a results graph
will show a straight line through the origin.

According to the equation these would be the values obtained for the
v² and this is what the results graph would look like.

Height / m

v² / m²/s²

0.04

0.78

0.06

1.18

0.08

1.57

0.10

1.96

0.15

2.94

0.20

3.92

0.25

4.91

[IMAGE]

Preliminary Work

From experimenting with the equipment we found many different things
whish could be amended in the method.

The jack and the ramp would have to be adhered to the work surface.
This would stop them from moving which would change measurements
slightly and make the results slightly inaccurate.

The distance travelled by the trolley will be one metre because that
is the simplest figure that could be used with the ramp.

The heights that will be used will be 0.04m, 0.06m, 0.08m, 0.10m,
0.15m, 0.20m and 0.25m because they are simple numbers and these are
the heights that can be measured safely. The lowest is 0.04m because
when the height is 0.02m the trolley stops moving before it reaches
the light gate. The highest is 0.25m because that is the highest
height achievable by using one jack. We will use 7 different heights
for our results to be reliable because 5 is too few data points to be
able to plot an accurate results graph.

The trolley will be released as opposed to pushed down the ramp so
that its speed is neither increased nor decreased.

We will use the light gate to measure the time taken for the trolley
to travel 10 cm at the end of the runway as opposed to measuring the
speed.

We tried out the method with random values to see if the results were
reproducible and reliable and they were.

Amended Method

The apparatus will be set up as above. The jack will be used to raise
the ramp to a certain height. The height of the start position of the
trolley will be measured and then the height of the end position of
the trolley would be measured using metre rulers and the difference of
these two measurements would give the height, h. The jack will then be
extended or contracted in order to get the specific heights for h
(0.04m, 0.06m, 0.08m, 0.10m, 0.15m, 0.20m, 0.25m).The light gate would
be connected to the QED and positioned at the end position of the
trolley. The trolley would be raised to the top of the ramp. It will
then be released down the ramp without any human force pushing it
down. The light gate would measure the time interval for the trolley
to pass through the light gate at the bottom of the ramp. For each
height the time interval for the trolley to pass through the light
gate will be measured 3 times. This will then be repeated for all of
the different heights.

Analysis

As the height of the ramp increased, so did the velocity.

[IMAGE][IMAGE]

The line of best fit on the graph is an exponential curve. This means
that the velocity increases until it gets to a certain height when all
of the velocities higher than that will be the same.

I squared the results for v to get the results for v². These are the
results for that.

Height / m

v² / m²/s²

0.04

0.24

0.06

0.586

0.08

0.937

0.10

1.06

0.15

1.93

0.20

2.87

0.25

3.84

I predicted that height would be directly proportional to v². By using
the equation: v²=2gh, I got these predicted results.

Height / m

2gh

0.04

0.78

0.06

1.18

0.08

1.57

0.10

1.96

0.15

2.94

0.20

3.92

0.25

4.91

[IMAGE]The graph below shows the results I got against my earlier
prediction.

The blue line shows the actual results I got and the pink line shows
my prediction. My prediction was that v² and height would be directly
proportional. The line of best fit would pass through the origin. My
results show the line of best fit passing below the origin. This means
that the v² results which I got were slightly below what was expected.

This is because there was friction between the wheels of the trolley
and the surface of the ramp. Also energy may have been lost by
friction in the axels of the trolley.

I calculated the efficiency by dividing the result that I got for a
particular height by what the result should have been according to the
equation: v²=2gh and then multiplied the answer by 100 to get the
efficiency in %.

Height

Efficiency

0.04

30.8

0.06

49.7

0.08

59.7

0.10

54.1

0.15

65.6

0.20

73.2

0.25

78.2

As you can see, the efficiency increases as the height of the ramp
increases.

[IMAGE]Why?

The first diagram shows a very horizontal ramp. This would mean that
its weight is going directly into the ramp. This would mean that there
is more friction and therefore there is more energy lost in the
transfer between gravitational potential energy and kinetic energy.
This energy would be lost as heat.

The second diagram shows a vertical runway. In this case, none of the
weight is going though the ramp and therefore there is no friction
between the trolley and the ramp. The third diagram shows a diagonal
ramp. More weight would be going through the ramp than in the second
diagram but less than in the first diagram, which means that the loss
of energy would be somewhere in between the energy loss in the first
two diagrams.

As the height increases, so does the angle. So as the angle increases,
less energy is lost as friction.

Evaluation

Our experiment was fairly successful even though our results did not
match the prediction. The measurement of the height may have been
difficult because we could only measure to the nearest mm.

[IMAGE]There is no anomalous data as such, but on the most of the
results graphs, you can see a distinct pattern. For the data points
for the heights, 0.04m, 0.06m and 0.08 you can see a totally different
line of best fit to the line of best fit of the other 4 data points.
This skewed the results slightly.

The reason that there are two lines of best fit is that the results
were taken on two separate occasions and two different trolleys were
used. Each trolley would have a certain amount of grip on the wheels
(causing friction between the wheels and the surface of the ramp) and
a certain amount of friction in the axels. This would mean that they
would lose different amounts of energy in the energy transfer and
therefore would travel at different speeds.

If I could redo the experiment I would improve it by:

* Using one trolley throughout the entire experiment in order to
obtain a more consistent set of results.

* By creating an environment in which there would be no friction.
This could be done by using an air track instead of a wheeled
trolley and a ramp. There would be little or no friction between
the track and the trolley.

* Although it is not possible with the resources available to me, I
could perform the experiment in a vacuum to take away the effect
of air resistance on the trolley.

An additional experiment to confirm my results would be to measure the
speed using the light gate instead of measuring time. This would also
eliminate the possibility of an error when measuring the length of the
runway.

I think that even though two trolleys were used, the results are still
fairly reliable. If you define anomalous data as pieces of data more
than 10% away from the line of best fit, there is no anomalous data.

How to Cite this Page

MLA Citation:
"Trolley Investigation." 123HelpMe.com. 19 Sep 2014
    <http://www.123HelpMe.com/view.asp?id=147751>.




Related Searches





Important Note: If you'd like to save a copy of the paper on your computer, you can COPY and PASTE it into your word processor. Please, follow these steps to do that in Windows:

1. Select the text of the paper with the mouse and press Ctrl+C.
2. Open your word processor and press Ctrl+V.

Company's Liability

123HelpMe.com (the "Web Site") is produced by the "Company". The contents of this Web Site, such as text, graphics, images, audio, video and all other material ("Material"), are protected by copyright under both United States and foreign laws. The Company makes no representations about the accuracy, reliability, completeness, or timeliness of the Material or about the results to be obtained from using the Material. You expressly agree that any use of the Material is entirely at your own risk. Most of the Material on the Web Site is provided and maintained by third parties. This third party Material may not be screened by the Company prior to its inclusion on the Web Site. You expressly agree that the Company is not liable or responsible for any defamatory, offensive, or illegal conduct of other subscribers or third parties.

The Materials are provided on an as-is basis without warranty express or implied. The Company and its suppliers and affiliates disclaim all warranties, including the warranty of non-infringement of proprietary or third party rights, and the warranty of fitness for a particular purpose. The Company and its suppliers make no warranties as to the accuracy, reliability, completeness, or timeliness of the material, services, text, graphics and links.

For a complete statement of the Terms of Service, please see our website. By obtaining these materials you agree to abide by the terms herein, by our Terms of Service as posted on the website and any and all alterations, revisions and amendments thereto.



Return to 123HelpMe.com

Copyright © 2000-2013 123HelpMe.com. All rights reserved. Terms of Service