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Deconstruct of Acceleration due to gravity - Coggle Diagram
Deconstruct of Acceleration due to gravity
Determining acceleration
Weight Force
formula is limited in the way that if data is input into the formula and there are errors present in the results, it will make the final result unreliable or inn-accurate
Will not be used
Linear motion formulae
There are many variables that must be taken into account when measuring the data which allows more scope for error in the results. Also, if the formulae are used to determine the acceleration, the raw data must be used which allows the errors to affect the reliability and accuracy more.
Linear motion formulae will not be used in the sense that the data will not be input directly into them, however, the relationship between the variables (directly/inversely proportionality) will be useful
Motion sensor
Could be used to purely measure the acceleration of the object outright
Could potentially make the data unreliable as it may pick up other motion in the background or not be perfectly aligned on the ball
Will not be used in this experiment as it has a greater potential for error than other methods of measuring acceleration/velocity
Graphing
Weight-mass graph
Weight and mass could be measured and then plotted. The slope of this graph would find the acceleration due to gravity
Does not suit an experiment when an object is being dropped from a height so will not be used
Velocity-time graph
Velocity and time could be measured and then plotted
. Sloped of the graph would give the acceleration due to gravity
Suitable variables being graphed for an experiment where an object is being dropped
Variables
Height (displacement)
Could be kept controlled
Would be difficult to get it to drop at the same height every time as a human will be dropping it however it will be a more direct way of finding the acceleration therefore cutting out a higher margin of error in the conversion of data
Will be kept controlled
could be used as the independent variable and the effect of changing the height on velocity (therefore acceleration)
not the most direct way to measure the acceleration due to gravity as graph would be displacement-time which would then have to be converted into velocity-time graph
Mass
use objects that have a different mass (e.g. different types of balls)
these will have different surface areas and be made of different materials, effecting the air resistance
Same ball will be used
Use the same ball but
change the psi
to change the mass of the ball
keeps the surface area and therefore air resistance controlled across the trials
Will
use this method
to change the mass of the object
Could be kept controlled
This is a possibility but I think that mass will be something that is easy to change without too many inconsistencies across the trials
Mass will be independent variable
Environment (Air resistance)
Surface area of the object is a factor of the effect of air resistance, the bigger the surface area, the slower the object will fall
The shape of the objects must be kept the same
in an effort to reduce the effect of air resistance and keep the results as consistent as possible e.g. all circular or all flat as well as have the same surface area. A ball pumped up to different psi will be used to reduces the effect of this
Experiment must be conducted in the same environment on the same day to control the effect of air resistance on the results as much as possible. Also there is a greater effect of air resistance outside if there is a wind or other weather condidtions
The experiment will be conducted inside a room with the door closed, the air conditioner off and the windows
closed in an effort to reduce the effect of air resistance.
Could be conducted in a vacuum to rule out the possibility of air resistance having an effect on the results
Limited as the school doesn't have this facility nor is there access to one to conduct this experiment
Everything possible will be done to reduce the effect of air resistance in the environment that we have available to us
Time
dependent
time will be measured and then plotted on velocity-time graph to find acceleration
independent/controlled
Both encounter similar limitations, very difficult to change/keep the time the same with just time as a factor as it is influenced by the other variables
will not be used as independent or controlled variable
Amount of force applied
independent
would be hard to change the force applied as the ball is being dropped by a human and there is no real way of measuring how much force they apply let alone keep it consistent throughout the experiment
Will be kept controlled
controlled
Ideally, no external force will be applied to the ball to isolate only weight force which means the amount of force applied will be kept constant. This is to ensure one variable is being changed at a time, keeping the test fair
Velocity
dependent variable in the experiment
will be plotted on a
velocity-time graph
where the slope will determine the acceleration due to gravity
Equipment
Stopwatch
Human reflex error: the presence of random error in results which will affect the reliability of the data as there will be a lapse in time from when the ball is dropped and the timer being started and then another from when the ball hits the ground and the timer is stopped
Stopwatch will still be used but more trials will be taken and timer will be on the ground
(at eye level) to reduce the lag between hitting the floor and the timer going off
Object to be dropped
Disney princess bouncy ball from home.
Can be pumped up and deflated but only limitation might be that it is too big for the light gate
If this is the case, it will be pumped up enough that the mass changes but that it can still fit through the light gate
Tape (to maintain same height)
There is not a physical barrier to rest the ball on/align the ball to make sure it is dropped from the same height each time
but will provide a visual aid to get it as similar as possible
Light gate
Only measures instantaneous velocity and only has a small area for the ball to fall through. Also could be a systematic error present if not calibrated correctly/at all
will be set up on the ground to record the ball's final velocity
(as initial velocity will be 0) so the change in velocity can be calculated. Also a small bouncy ball will be used so it can fit through the gap.
Pump
needs to be able to stop quickly to make sure the ball has the right mass but also deflate if it is over pumped
Electric ball pump in the sports shed will be used
Scales
Needs to be accurate in order to make sure that the ball is precisely the right mass
Digital scales from the chemistry lab will be used
Reduction of errors
Random
Number of trials
1
Any random errors present will have a large effect on the results that have been taken, making them less reliable. This will be evident in the scattering of the graph
Will do more than one trial to try and reduce the effect of random errors
2
Will slightly reduce the effect of random error when averaged out but will not have that much of an effect
Will do more than two trials to further reduce the effect of random error
3
Will reduce the effect of random errors the most as it has the most trials and the average will have a more reliable representation of the proper results
Will do three trials
for each each test and then average them out
Line of best fit
Gives a better indication of where the data points should lie on the graph therefore reducing the effect of random errors as it brings the data closer to its true values
Will definitely be used on final graph and points along the line will be used for any calculations
NOT ones from the table
Systematic
Finding the gradient
Using the gradient of the line of best fit reduces the effect of systematic error as it does not change regardless of where the line falls on the plane. This is important as systematic errors shift all the points either up or down by the same amount but the gradient is still the same
Will be used to find the acceleration
