A scale measures the following weight of a light object
[tex]11.000\pm0.034\; lb[/tex]
Here 0.034 is the uncertainty in the measurement.
It is given that the percent uncertainty of the scale remains constant.
So, the percent uncertainty of the scale is
[tex]\frac{0.034}{11.000}\times100=0.309\%[/tex]
Now, we can use this percent uncertainty of the scale to find the uncertainty for the measurement of 78.000 lb
[tex]\frac{0.309}{100}\times78.000=0.240\; lb[/tex]
Therefore, the uncertainty for measurement of 78.000 lb is 0.240 lb
