Week - 1 - Consistency of Units
Aim:-
- To convert the given SI unit values of given quantities to all different parameters.
- To prepare consistent unit system table for different unit system.
Procedure:-
System of Units:
- A system of units is a set of realated units that are used for calculations. For example, in the MKS unit system, the base units are the meter, kilogram and second which represents the base dimensions of length, mass and time respectively. In this system, the unit of speed is the meter per second.
SI Units Of Fundamental Quantity:-

SI Units of Derived Quantity:-

Value of the following measurements are given as follows:
- Mass= 1 kg
- Length= 1m
- Time= 1s
- Force= 1N
- Stress= 1Pa
- Energy= 1Nm
- Density= 1Kg/m3
- Youngs Modulus= 210Gpa
- Velocity= 56.33kmph
- Gravity= 9.8 m/s2
Conversion of SI units to gm mm ms system:-
1) Mass = 1 Kg = 1000 gm
2) Length = 1m = 1000mm
3) Time = 1 sec = 1000ms
4) Force = 1 N F = Mass X Acceleration = 1 Kg * 1m/s2 =(1000gm*1000mm)/(1000ms)2 = 1 (gm*mm)/ms2
5) Stress = 1 Pa 1Pa = 1N/m 1N= 1(gm*mm/ms2) = {1(gm*mm/ms2)} / (1000mm2) = 1*10-6gm/mm*ms2
Conversion Factor = 10-6gm/mm*ms2
6) Energy = 1Nm = 1N*1m = {1gm*mm/ms2}* 1000mm = 1000 gm*mm2/ms2 = 103 gm mm2/ms2
Conversion Factor = 103 gm mm2/ms2
7) Density = 1Kg/m3 = 1000gm/(1000mm) = 1 gm/1000000 mm3 = 106 gm/mm3
Conversion Factor = 106 gm/mm3
8) Youngs Modulud = 210 GPa 1 Pa= 10-6 gm/mm ms2 1 Gpa= 109*10-6 gm/mm ms 210 GPa= 210*103 gm/mm ms2
Conversion Factor = 103
9) Velocity= 56.33 Kmph 1 Km = 1000000 mm = 106 mm 1 Hr = 60 min*60sec*1000 = 36*105 ms 1 Kmph = (106)/(36*105) = 0.277 mm/ms For 56.33 Kph; = 56.33* 0.277 mm/ms = 15.60 mm/ms
Conversion Factor= 0.277
10) Gravity = 9.88 m/s2 1m/s2 = 1000mm/(1000ms2) = 10-3 mm/ms2 9.88 m/s2 = 9.8*10-3 mm/ms2
Conversion Factor= 10-3
Calculation Table:-
| Unit System | MASS (1Kg) | LENGTH (1m) | TIME (1s) | FORCE (1N) | STRESS (1Pa) | ENERGY (1Nm) | DENSITY (1Kg/m3) | YOUNGS MODULUS (210GPa) |
VELOCITY (56.33kmph) |
GRAVITY (9.8m/s2) |
| Kg cm ms | 1 kg | 100 cm | 1000 ms | 10-4 (kg*cm)/ms2 | 10-8 kg/cm ms2 |
10-2 kg cm2/ms2 |
10-6 kg/cm3 |
210 * 106 kg/cm*ms2 | 0.1560 cm/ms |
9.8*10-4 cm/ms2 |
| Kg cm s | 1 kg | 100 cm | 1 s | 100 kg cm/s2 | 10-2 kg/cm s2 |
104 kg cm2/s2 |
10-4 kg/cm3 |
210 * 107 kg/cm*s2 | 156.03 cm/s |
cm/s2 |
| gm mm ms | 1000 gm | 1000 mm | 1000 ms | 1 (gm*mm)/ms2 | 1*10-6gm/mm*ms2 | 103 gm mm2/ms2 | 106 gm/mm3 | 210*103 gm/mm ms2 | 15.60 mm/ms | 9.8*10-3 mm/ms2 |
| kg m s | 1 kg | 1 m | 1 s | 1 kg m/s2 | 1 kg/m s2 |
1 kg m2/s2 |
10 kg/m3 |
210 * 109 kg/m s2 | 15.603 m/s |
9.8*1 m/s2 |
| g cm s | 1000 gm | 100 cm | 1 s | 105 g cm/s2 | 10 g/cm s2 |
107g cm2/s2 |
10-3 g/cm3 |
210 * 1010 g/cm s2 | 156.03 cm/s |
9.8*100 cm/s2 |
| g cm us | 1000 gm | 100 cm | 106 us | 10-1 g cm/us2 | 10-3 g/cm us2 |
10g cm2/us2 |
10-3 g/cm3 |
210 * 106 g/cm us2 | 0.000156 cm/us |
9.8*10-10 cm/us2 |
| g mm s | 1000 gm | 1000 mm | 1 s | 106 g mm/s2 | 1 g/mm s2 |
109 g mm2/s2 |
10-6 g/mm3 |
210 * 109 g/mm s2 | 15603 mm/s |
9.8*1000 mm/s2 |
| ton mm s | 0.001 ton | 1000 mm | 1000 ms | 10-6 ton mm/ms2 | 10-12 ton/mm ms2 |
10-3 ton mm2/ms2 |
10-12 ton/mm3 |
210 * 10-3 ton/mm ms2 | 15.60 mm/ms |
9.8*10-3 mm/ms2 |
| slug ft s | 0.0068 slug | 3.28 ft | 1 s | 0.22 slug ft/s2 | 0.0205 slug/ft s2 | 7216 slug ft2/s2 | 0019 slug/ft3 | 4.305*109 slug/ft s2 | 51.316 ft/s | 32.14 ft/s2 |
| kg mm s | 1 kg | 1000 mm | 1 s | 1000 kg mm/s2 | 10-3 kg/mm s2 | 106 kg mm2/s2 | 10-9 kg/mm3 | 210 * 106 kg/mm s2 | 15603 mm/s | 9.8*1000 mm/s2 |
| g cm ms | 1000 gm | 100 cm | 1000 ms | 10-1 gm cm/ms2 | 10-3 gm/cm ms2 | 10 gm cm2/ms2 | 10-3 g/cm3 | 210 * 106 g/cm ms2 | 1.5603 cm/ms | 9.8*10-4 cm/ms2 |
| kg mm ms | 1 kg | 1000 mm | 1000 ms | 10-3 (kg*mm)/ms2 | 10-9 kg/mm ms2 |
1 kg mm2/ms2 |
10-9 kg/mm3 |
210 * 1 kg/mm ms2 | 15.60 mm/ms | 9.8*10-3 mm/ms2 |
Conclusion:-
- Convert the given SI unit values of given quantities to all different parameters with detailed calculation.
- Prepare the consistent unit system table for different unit system.