Page 21 - WCS - Electrical

WORKSHOP CALCULATION & SCIENCE - CITS

3 2 5 6
(1 X 10) + (2 X 1) + + + +
10 100 1000 10000

5 35 127 3648
Total Length of pin = 2.25 + 55.36 + 12.18 = 0.0127, = 3.648
=
Ex.
0.5,
0.35
=
100
10 = 69.79 mm 10000 1000

Cutting allowance = 3 mm 0.750.25
Total Length = length of pin + cutting allowance
75
100
0.75
=
x
= 69.79 mm + 3 mm
25
0.25
100
25
3
75 =
= 72.79 mm
Length of the bar = 900 mm
No.of pins to be cut = 900 = 12.394
72.79
= 12 pins
Left out material = Total length - length of pin + cutting allowance
= 900 - 12 x 69.79 + 12 x 3
= 900 - 837.48 + 36
= 900 - 873.48
Left out length = 26.52 mm
Conversion of Decimals into fractions and vice-versa
• Convert decimal into fractions

Example
Convert 0.375 to a fraction
375 15 3 2 7 3
Now place 1 under the decimal point followed by as many zeros as there are numbers 10) + (3× 1) + + +
0.375 =
(5×
100) +
(4×
=
=
=
375 15 100 40 8 2 7 10 100 100
3
3
=
0.375 = 375 15 3 = (4× 100) + (5× 10) + (3× 1) + + 2 7 + 3
= 3
273

1000.375
10
=
8
+
+
10) +
0.375 = 40 = 8 = = (4× 100) + 453 1000 (3× 1) + 100 100
(5×
=
3 100 40 8 273 10 100 100
0.375 = 3 375 15 3 = 453 273 2 7 3
8 0.375 =
1000(4×=
0.375 = 9 100 = 40 = 8 = 453 100) + (5× 10) + (3× 1) + 10 + 100 + 100
8
• Convert fraction into decimal 1000 273 21 = 7 = 0.875
3
9 0.375 = 16 = 453 24 8
7
Example 8 21 1000
=
16 9 21 = 7 0.875
• Convert to a decimal 24 8 = = 0.875

0.5625
16 24 8 625 5 1
16
90000
9
Proceed to divide in the normal way of division but put 0.0625 = 10000 = 80 = 16
7
21

0.5625
0.875
16 90000 16 0.0625 = 625 = = 8 5 = = 1
0.5625
24

10000
90000
16
9
=
=
zeros (as required) after the number 9 (Numerator) 0.0625 = 625 80 5 16 1
0.5625 10000 80 16
16
9 16 90000 0.0625 = 625 = 5 = 1
16 9 10000 80 16
16 1 , 2 , 1
93 3 7
1 2 1
, , 16
1
7
3 1 , 2 , 1 10000
3
3 3 7 = = 0.3333 − Recurring

1 10000 1 3 2 1 3 8
,
= = , 0.3333 − Recurring
7
3 1 = 3 10000 33 2 = 20000 Recurring
CITS : WCS - Electrical - Exercise 1
0.3333 −
3 3 = = 0.666 − Recurring

2 20000 100001 3 3
= = = 0.666 − = Recurring Recurring0.3333 −
20000 33
3 2 = 3 = 0.666 − Recurring
3 3  1 = 10000 = 0.14285714 2 − Recurring 


2  7
 1 10000 = 200007 = 0.666 − Recurring  
 = 3 = 0.14285714 2 − Recurring 
3
 7  1 = 7 10000 = 0.14285714 2 − Recurring 



 7 7 
 1 10000 
 = = 0.14285714 2 − Recurring 
 7 7 