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Solved physics Paper 5??

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geek101

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minie23 said:
The worst line should pass through the first and last tip of the error bars ?
Is it compulsory ?
What about the best fit line ?
Click to expand...

the line of best should be one which passes through most of the points, and should usually have an equal number of points either above it or below it. the line of worst fit has to pass through all the error bars, and yep it should either be from the start of the first error bar to the end of the last error bar, or the end of the first error bar to the start of the last error bar :)
 
minie23

minie23

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geek101 said:
the line of best should be one which passes through most of the points, and should usually have an equal number of points either above it or below it. the line of worst fit has to pass through all the error bars, and yep it should either be from the start of the first error bar to the end of the last error bar, or the end of the first error bar to the start of the last error bar :)
Click to expand...

Okay ! Thanks !
coz sometimes the line of worst fit does not pass on the error bars ! So, I have to make to make it pass atleast on the first and last error bar !
 
ash369

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Aoa! Guys can you help me clear my concepts about uncertainties and percentage uncertainties please? Might come in handy for my P52 on the 4th! :unsure:
 
ash369

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Also, I'd need help with logarithmic equations, exponential functions, exponential and power law variations! Any help will be appreciated!
 
Praveena

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I mostly get confuse with error bars?
can you plz tell about error bars in detail
 
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raamish

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Guys this is an answer to qs 1 of j07. I want to know the correct way of writing the answer. I have posted my answer to question 1 below. If there are any problems with my answer please tell me so that i can correct my answer. Thanku in advance.

In this experiment the independent variable is r and the dependant variable is v, the terminal velocity of the object. A constant variable in this experiment is temperature. Another constant variable is the distance when time is being measured.

We will calculate the diameter of the ball by using vernier calipers and then we will calculate the radius by using the formula d=r/2. We take metal balls of different radii to vary r. We measure the time taken for the ball to fall a fixed distance through the oil. To ensure the ball falls through a fixed distance we place fudicial markers on the container. We will measure the time taken for the ball to fall through two fixed points of the container at terminal velocity. Then we will calculate the terminal velocity of the ball by using the formula v=s/t. We will take multiple trials for each ball and then take out the average speed to reduce random errors in the experiment.
To ensure the ball has reached terminal velocity we will place fiducial marks well below the surface of the oil. We will take the diameter of the ball at different points of the ball and calculate the average. The oil used in the experiment should be clear and the container should be wide and transparent.
After calculating all the required values will plot a graph of v against r2. If the graph has a straight line passing through the origin then relationship has been confirmed. One safety precaution is to prevent the oil ffrom being near any fire because it may be flammable.
 
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geek101

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Praveena said:
I mostly get confuse with error bars?
can you plz tell about error bars in detail
Click to expand...
now see, for the error bars lets say the error is +- 0.5 and the point is 22 for the x axis
then the error bar must be from >> 21.5 and 22.5
how do you make the error bar now, for this you must see what is the value of one square on the x-axis. Lets assume one box on the x axis is 0.05. Which means and error of 0.5 on each side will cover 10 boxes on the x axis. To draw the error bar you will draw a horizontal line (because error is for a value on the x-axis) which will be 10 boxes behind 22 and 10 boxes ahead of it!
If the point 22 was for the y axis, then the error bar would be a vertical line of 10 boxes above and below 22.

hope this can help :)
 
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raamish

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geek101 said:
now see, for the error bars lets say the error is +- 0.5 and the point is 22 for the x axis
then the error bar must be from >> 21.5 and 22.5
how do you make the error bar now, for this you must see what is the value of one square on the x-axis. Lets assume one box on the x axis is 0.05. Which means and error of 0.5 on each side will cover 10 boxes on the x axis. To draw the error bar you will draw a horizontal line (because error is for a value on the x-axis) which will be 10 boxes behind 22 and 10 boxes ahead of it!
If the point 22 was for the y axis, then the error bar would be a vertical line of 10 boxes above and below 22.

hope this can help :)
Click to expand...
can u check the answer i posted above too plzz
 
Silent Hunter

Silent Hunter

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errors and sf?

any body can help ?
in what sf should we write the errors ? ...... and including errors of log functions ....?

geek101

biba


or any one?
 
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geek101

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Silent Hunter said:
errors and sf?

any body can help ?
in what sf should we write the errors ? ...... and including errors of log functions ....?

geek101

biba


or any one?
Click to expand...

from the questions that iv done before, the error value is usually stated to 1 or 2 significant figures. like 0.0182 for example can be written as +-0.02 or +-0.018, i think both are acceptable.
 
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