Physics isa Help

Why would you use absolute uncertainty? Is there any specific explanation or any justification to use absolute uncertainty?

Yes, when you add or subtract two values, each with an absolute uncertainty, you add the absolute uncertainties to get the total uncertainty.

This is the rule.

When adding or subtracting values, add the absolute uncertainties.
When multiplying or dividing values, add the % uncertainties.

What about the uncertainty where you calculate the range of measurements and divide by 2? Is there a specific reason why you would use this uncertainty?

Are you asking why uncertainty is used in practical physics?

Uncertainty is combined by adding the % uncertainties in the two quantities when they are multiplied or divided in a formula.

In your formula for volume the quantities are multiplied so add the % uncertainties in r and h to get the % uncertainty in V.
As r is squared you need to double its % uncertainty.

This is a standard procedure in practical physics.

Rearrange the formula for k (which you did in the previous part) and find its value.
On the other side of the formula you have T², m, x and L either multiplied or divided.
So the % uncertainty in k is the sum of the % uncertainties in m, x, and L plus 2 times the % uncertainty in T (as it's T²).

Thanks so much for replying

yes i did that and got the percentage uncertainty to be 5.1% but it isnt asking for the percentage uncertainty but for the uncertainty of the constant which is apparently 2 i dont know how they got to that.

Well what is 5% of that value?

If I had a value of, say, 200 and it was ± 5% then I would find 5% of 200, which is 10, and then say the value is

200 ±10

Yes but I dont already have that value im asked to work it out . The question wants the uncertainty of k but I go up to working out the perentage uncertainty and then dont know how to convert it. Thanks