Week - 1 - Consistency of Units
Aim : The Aim of this challenge is to convert data from one unit sytem to other unit system and
to write their conversion factors.
For conversion from SI unit to gm/mm/ms unit system:
The SI unit is written as by mass in 'kg', length in 'm' and time in 's'. Other quantities are calculated from the fundamental quantities. Given in the problem are:
Mass :1kg
Length :1m
Time :1s
Force :1N
Stress :1Pa
Energy :1Nm
Density :1Kg/m3
Young's Modulus :210GPa
Velocity :56.33KMPH
Gravity :9.8m/s2
To convert the above mentioned quantities to gm/mm/ms system of units:
1 kg = 1000 gm
1 m = 1000 mm
1 s = 1000 ms
FORCE
Force of 1 N in SI units is given by
Force(N) = Mass(m) X Acceleration due to gravity(g)
1 N = 1 kg X 1 m/s2
Converting the above into gm/mm/ms form we get,
1N = (1000gm * 1000mm)/10002ms2
1 N = 1 gm mm/ms2
STRESS
The definition of stress is given by force acting per unit area. Stress (σ) and its SI unit is Pa
Stress = Force/Area
1 Pa = 1 N/1 m2
1Pa = (1gm mm/ms2)/0.0012
1 Pa = 106 gm /mm s2
ENERGY
The energy is given by amount of work done i.e force * displacement. The unit of energy is Nm.
Energy = Force * displacement
1 N-m = 1 N * 1m
1 N-m = 1.00 gm mm/ms2 * 0.001 mm
1 N-m = 10-3 gm-mm2/ms2
DENSITY
Density is defined as mass per unit volume. The unit of density is kg/m3 in SI unit.
Density = mass (kg) / volume(m3)
1 kg/m3 = 0.001 gm / (0.001)3
1 kg/m3 = 106 gm/mm3
YOUNG’S MODULUS
Young’s Modulus is the elastic strength of a material.
The unit of Young’s modulus is GPa.
For the given material, the value of Young’s modulus is 210 GPa.
To convert to gm/mm/ms
210 GPa = (210 * 109 * 106 gm mm/ms2 )/ mm2
210 GPa = 2.10 * 1018 gm mm/ms2
VELOCITY
Velocity is displacement per unit time. Its unit in SI system is m/s. Given in the problem is 56.33 kmph.
56.33 kmph = 56.33 * 103 * 0.001 / 3600 * 0.001
56.33 kmph = 15.37 mm/ms
GRAVITY
Gravity is same acceleration due to gravity and is calculated from the law of gravitational force equation. Its value on earth is estimated as 9.8 m/s2 in SI unit.
9.8 m/s2 = 9.8 * 0.001 / 0.0012
9.8 m/s2 = 9800 mm/ms2
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