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a= 1.3mm +- 0.1mm

b= 2.8mm +- 0.2mm

c= 0.8mm +- 0.1mm

Q=ab^2/sqrt(c)

Calculate Q with its uncertainty

b= 2.8mm +- 0.2mm

c= 0.8mm +- 0.1mm

Q=ab^2/sqrt(c)

Calculate Q with its uncertainty

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#2

(Original post by

a= 1.3mm +- 0.1mm

b= 2.8mm +- 0.2mm

c= 0.8mm +- 0.1mm

Q=ab^2/sqrt(c)

Calculate Q with its uncertainty

**Rauhan**)a= 1.3mm +- 0.1mm

b= 2.8mm +- 0.2mm

c= 0.8mm +- 0.1mm

Q=ab^2/sqrt(c)

Calculate Q with its uncertainty

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(Original post by

What have you tried so far?

**BobbJo**)What have you tried so far?

1) Calculate the value of Q

2) Calculate %uncertainty for each quantity

3) Calculate the value of uncertainty

4) Express Q with its uncertainty

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(Original post by

So my teacher divided the question into 4 parts and then asked us to solve it.

1) Calculate the value of Q

2) Calculate %uncertainty for each quantity

3) Calculate the value of uncertainty

4) Express Q with its uncertainty

**Rauhan**)So my teacher divided the question into 4 parts and then asked us to solve it.

1) Calculate the value of Q

2) Calculate %uncertainty for each quantity

3) Calculate the value of uncertainty

4) Express Q with its uncertainty

1)11.39

2) a=7.4%

b= 7.14%

c=12.5%

3) Now i am stuck

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#5

**Rauhan**)

So my teacher divided the question into 4 parts and then asked us to solve it.

1) Calculate the value of Q

2) Calculate %uncertainty for each quantity

3) Calculate the value of uncertainty

4) Express Q with its uncertainty

For 3) Use the fact that when you multiply/divide by a quantity you add the percentage uncertainty,

i.e (a +- x%) x (b +- y%) = ab +- (x+y)%

and (a +- x%) / (b +- y%) = a/b +- (x+y)%

And also the fact that, a +- x%)^n = a^n +- n(x%)

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(Original post by

Yes that's correct.

For 3) Use the fact that when you multiply/divide by a quantity you add the percentage uncertainty,

i.e (a +- x%) x (b +- y%) = ab +- (x+y)%

and (a +- x%) / (b +- y%) = a/b +- (x+y)%

And also the fact that, a +- x%)^n = a^n +- n(x%)

**BobbJo**)Yes that's correct.

For 3) Use the fact that when you multiply/divide by a quantity you add the percentage uncertainty,

i.e (a +- x%) x (b +- y%) = ab +- (x+y)%

and (a +- x%) / (b +- y%) = a/b +- (x+y)%

And also the fact that, a +- x%)^n = a^n +- n(x%)

If I am right??

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#7

2) For a, the percentage uncertainty should be 7.69%

The percentage uncertainty for b^2 is twice the uncertainty for b.

The percentage uncertainty for c^(1/2) is half the uncertainty for c

3) Add the percentage uncertainties you get

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#8

The uncertainty for b is not the same as the uncertainty for b^2

The uncertainty for sqrt(c) is different too

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(Original post by

Close, but not quite!

The uncertainty for b is not the same as the uncertainty for b^2

The uncertainty for sqrt(c) is different too

**BobbJo**)Close, but not quite!

The uncertainty for b is not the same as the uncertainty for b^2

The uncertainty for sqrt(c) is different too

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#10

(Original post by

If u dont mind, can u solve the whole question step by step

**Rauhan**)If u dont mind, can u solve the whole question step by step

b= 2.8mm +- 0.2mm

c= 0.8mm +- 0.1mm

Q= ab^2/sqrt(c)

Doing the question as per the steps given by your teacher:

1)

2)Percentage uncertainty in %

Percentage uncertainty in

= 2 x Percentage uncertainty in b = 14.28%

Percentage uncertainty in \sqrt c

= Percentage uncertainty in c^(1/2)

= 1/2 x Percentage uncertainty in c

= 6.25%

3)%

%

Hope this helps

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(Original post by

a= 1.3mm +- 0.1mm

b= 2.8mm +- 0.2mm

c= 0.8mm +- 0.1mm

Q= ab^2/sqrt(c)

Doing the question as per the steps given by your teacher:

1)

2)Percentage uncertainty in %

Percentage uncertainty in

= 2 x Percentage uncertainty in b = 14.28%

Percentage uncertainty in \sqrt c

= Percentage uncertainty in c^(1/2)

= 1/2 x Percentage uncertainty in c

= 6.25%

3)%

%

Hope this helps

**BobbJo**)a= 1.3mm +- 0.1mm

b= 2.8mm +- 0.2mm

c= 0.8mm +- 0.1mm

Q= ab^2/sqrt(c)

Doing the question as per the steps given by your teacher:

1)

2)Percentage uncertainty in %

Percentage uncertainty in

= 2 x Percentage uncertainty in b = 14.28%

Percentage uncertainty in \sqrt c

= Percentage uncertainty in c^(1/2)

= 1/2 x Percentage uncertainty in c

= 6.25%

3)%

%

Hope this helps

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