Measurement
1 . Ruler
Generally have the smallest scale of 1mm or 0.1 cm
2. Calipers
.
Calipers are used to measure the outside diameter of the cylinder , the depth of the tube , and the inside diameter . Accuracy was 0.1 mm or 0.01 cm
How to measure :
Read the scale fixed
Coupled with the search for the straight line between the fixed scale and Nonius scale ( below )
3 . Micrometer screw
Micrometer screw is generally used to measure the diameter of the ball / cylinder and the thickness of a thin plate and datar.Ketelitian reached 0.01 mm or 0.001 cm .
How to use :
Satuanya : mm
Value of each scale 0.5 mm
Nonius scale roll:
unit - mm
Each scale : 0.01 mm
The final result is the sum of the values on the main scale to scale rotary Nonius
Measurement accuracy
Precision measuring instruments is determined by :
Accuracy = 1/2 x smallest scale
1 . Ruler has accuracy = 1/2 mm
2 . Vernier caliper has ketilitian = ½ x 0.1 mm = 0.05 mm
3 . Has a precision micrometer screw = ½ x 0.01 mm = 0.005 mm
Important figures
1 . All numbers except the zeros are significant figures
2 . Number of zeros is trivial if :
• The zero flanked by a nonzero number of significant figures
Example : 304
• The zero on the right number of significant figures merupkan nonzero if given a special mark ( niasanya with an underscore )
example :
3.50 cm has three significant figures
2.50 cm memilii two significant figures
3 . Zeros on the left who are non-zero numbers are significant figures not
example :
• The length of 0.72 cm cube has two significant figures
• The length of 0.0702 cm cube has three significant figures
• The length of 0.7020 cm beam has three significant figures
• The length of 0.7020 cm cube has four significant figures
Measurement results reported
Measurement results is not absolute results , but one of the values that may be a number of measurement results . Due to the measurement results are reported as a range of possible values stated the actual length of objects
example
An object is measured with a ruler that has the smallest scale 1mm .
Ketelitien bar 0.5 mm
Results of measurement 4.44 cm , then the length of the actual object that is probably the
Minimum value = ( 4.44 to 0.5 ) mm
Maximum value = ( 4.44 +0.5 ) mm
Usually measurement results are reported as ( 4.44 ± 0.5 ) . Meaning of this paper that the measurement results may not exceed 0.5 mm . . Ruler Calipers Micrometer Screw <
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