TASARIMDAN İMALATA
Engineering Units and Conversions
Consistent units matter as much as numerical values in force, work, power and pressure calculations. Kilogram measures mass and newton force; kW denotes power and kWh energy.
Seven SI base units
| Quantity | Unit | Symbol |
|---|---|---|
| Length | metre | m |
| Mass | kilogram | kg |
| Time | second | s |
| Electric current | ampere | A |
| Thermodynamic temperature | kelvin | K |
| Amount of substance | mole | mol |
| Luminous intensity | candela | cd |
Basic mechanical relations
| Quantity | Relation | Condition |
|---|---|---|
| Force | ΣF = m × a | m: mass; a: acceleration. 1 N = 1 kg·m/s². |
| Work | W = F × d × cos(θ) | For constant force; θ is the angle between force and displacement. 1 J = 1 N·m. |
| Average power | P = W / t | Work W performed over time t. 1 W = 1 J/s. |
| Energy | E = P × t | For constant power; using SI units gives joules. |
| Pressure | p = F / A | For normal force distributed uniformly over an area. 1 Pa = 1 N/m². |
Example: a 2 kg mass under g = 9.81 m/s² has a weight force of about 19.62 N. Do not use a mass value directly as newtons.
Common conversions
- 1 kgf = 9.80665 N
- 1 kp = 1 kgf
- 1 J = 1 N·m = 1 W·s
- 1 kWh = 3.6 × 10⁶ J = 3.6 MJ
- 1 bar = 100 kPa = 100000 Pa
- 1 atm = 101325 Pa
- 1 kgf/cm² = 98066.5 Pa
- 1 psi ≈ 6894.757 Pa
- 1 in = 25.4 mm
- 1 ft = 12 in = 0.3048 m
- 1 ha = 10000 m²
- 1 daa = 1000 m²
- t[°C] = (t[°F] − 32) × 5/9
- T[K] = t[°C] + 273.15
- 2π rad = 360°
Unit symbols are case-sensitive: kg, s, kW, kPa and MPa. W as a variable for work differs from W as the unit watt.