# lab 2 question 18

## lab 2 question 18

Question 18: (2 points)

Lab 2 Part II Average of From Repeated Measurements and its Random Error - Error:

Equation (5") in "Error and Uncertainty" gives the random error of the average for measurements of the quantity t . Written for the absolute error of the average with = 5 measurements, it is:
(Use g_1 for, ...., gavg for )

guest
Guest

## lab 2 question 18

anyone know the answer? im entering in sqrt(g_1-gavg)^2+(g_2-gavg)^2+(g_3-gavg)^2+(g_4-gavg)^2+(g_5-gavg)^2)/5(5-1)) but it doesnt seem to be working

guest
Guest

## Re: lab 2 question 18

I think you may just have a problem with the parentheses.

it should be sqrt((g_1-gavg)^2+(g_2-gavg)^2+(g_3-gavg)^2+(g4-gavg)^2+(g_5-gavg)^2)/(5(5-1))

Guest5
Guest

## Re: lab 2 question 18

I think your just putting it incorrect. did you make a space after sqrt then the rest..the system is really specific but everything you have there is right

sqrt (((g_1-gavg)^2+ etc till 5 and then at the end close it like this gavg)^2/(20)) whatever your number is

that should work

good luck

tiffylov
Guest

## lab question 18

seems both those answers are incorrect on mine still, could someone copy paste a right answer out of their lab to see if something is wrong with mine, thanks

guest
Guest

## Re: lab 2 question 18

Try this, the "How did I do link" shows it is correct.

sqrt(((g_1-gavg)^2+(g_2-gavg)^2+(g_3-gavg)^2+(g_4-gavg)^2+(g_5-gavg)^2)/(20))

Also have any of you entered in Question 9 for both DeltaV/V= and DeltaV=? And on Question 12 I don't know the answer they are looking for for the acceleration of gravity (a=_____)?

Guest01
Guest

## Question 9

Question 9 for Lab 2 pt. B:

Question 12:

a = g

Does anyone know how to do #7 and # 15?

periwinkle

Posts : 22
Join date : 2008-09-17

## #7 & #15

#7
sqrt(DeltaA^2+DeltaB^2)

#15
abs(g-g_acc)/Deltag

gujugodd
Guest

## question 10,11,12,17

question 10, what numbers did you guyz put?? mine doesn't working. i don't know why!
question 11, what is the error delta v??
question 12- what is the intercept of b??
question 17- i think i did right but i keep getting a wrong answer!! plz help me~~ thank you~=)

Park

Posts : 6
Join date : 2008-09-18

## Re: lab 2 question 18

Question 10
If you haven't entered in any of the previous information, such as number values or the ever redundant "sqrt(Delta_N/N)" nonsense. If neither of these are entered Maple TA will mark you values as wrong. Enter in your formulas too since Maple TA will calculate them itself it seems. If everything previously has been entered correctly, go over the calculations again and make sure you are using the right ones.

D will be the measured value of the ruler from the beginning of the first masking tape to the beginning of the last masking tape.
N is the number of intervals. One interval includes both the masking tape and the clear section immediately following the masking tape.
d is the measured distance divided by the number of masking tape intervals on the ruler.
ΔD (ends of ruler) is given to you in the lab manual. It is half a millimeter. I converted it to S.I.; meters or 0.0005m.
ΔD This is obtained by plugging in ΔD (ends of ruler) into Equation 6 of Error And Uncertainty.
Δd is ΔD divided by the number of intervals on your ruler, just as you did to get d

[Tried to include a photo of the ruler for a visual but I'm having trouble, I will try to get it up later as per requested].

[b]Question 11[b]
ΔV= V*(Δd/d).
The error should be different for each of the five measurements. (Δd/d) will be the same number and your velocity will change.

[b]Question 12[b]
Our Velocity Vs. Time Graph should be a positive linear line. This graph is usually expressed mathematically as y=mx+b. For Question 1 on the Lab Report Sheet we express velocity as a function time (which is also given to us on the Course CD, forget the chapter number). V(t)=Vo+a*t [NOTE: Vo is your initial velocity]. Both are the same equations just expressed differently. Think of it as V(t)=a*t+Vo or even y=a*t+Vo

[b]Question 17[b]
Again, the redundant expression writings. You have to enter these just correctly or else Maple TA turns into a cock block. Double check how it is written out, include parenthesis and remember to close them. It is just a simple average formula, so (1+2+3+...N)/N. (g_1+g_2+g_3+g_4+g_5)/5 should suffice.

Guest01
Guest