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Mass Weight

Reference data and engineering information about mass weight for miscellaneous applications.

massweight

Overview

Engineering reference data for Mass Weight in miscellaneous.

Key Formulas

Unit Conversion

y=xky = x \cdot k

Multiply by conversion factor.

Linear Interpolation

y=y1+(xx1)(y2y1)x2x1y = y_1 + \frac{(x - x_1)(y_2 - y_1)}{x_2 - x_1}

Estimate between two known points.

Percentage

p=partwhole×100%p = \frac{\text{part}}{\text{whole}} \times 100\%

Part as fraction of whole.

Variables

SymbolDescriptionUnit
xxInput value
yyOutput value
kkConversion factor

Mass of Fundamental Particles

3 rows
Mass values of fundamental atomic particles.
Particle
Mass(kg)
Electron9.1095 × 10⁻³¹
Proton1.67265 × 10⁻²⁷
Neutron1.67495 × 10⁻²⁷

Source: engineeringtoolbox.com

Unit Systems for Mass and Weight

3 rows
Comparison of base units for mass and weight in common unit systems.
System
Mass Unit
Force (Weight) Unit
International System (SI)kilogram (kg)Newton (N)
British Gravitational (BG)slugpound-force (lbf)
English Engineering (EE)pound-mass (lbm)pound-force (lbf)

Source: engineeringtoolbox.com

English Engineering System Proportionality Constant

In the English Engineering (EE) system, a proportionality constant gcg_c is introduced to reconcile force and mass units. Newton's Second Law is modified as:

F=magcF = \frac{m a}{g_c}

For weight (force), this becomes:

Fg=maggcF_g = \frac{m a_g}{g_c}

The constant gcg_c is defined by the standard acceleration of gravity:

gc=1lbm×32.17405ft/s21lbf=32.17405lbmftlbfs2g_c = \frac{1 \, \text{lbm} \times 32.17405 \, \text{ft/s}^2}{1 \, \text{lbf}} = 32.17405 \, \frac{\text{lbm} \cdot \text{ft}}{\text{lbf} \cdot \text{s}^2}

This relationship also defines that 1 slug = 32.17405 lbm.

Example: Weight on Earth vs. the Moon

The acceleration of gravity on the moon is approximately 16\frac{1}{6} of that on Earth (gearth9.81m/s2g_{earth} \approx 9.81 \, \text{m/s}^2).

Weight on Earth: Fg,earth=m×gearth=(1kg)×(9.81m/s2)=9.81NF_{g, \text{earth}} = m \times g_{\text{earth}} = (1 \, \text{kg}) \times (9.81 \, \text{m/s}^2) = 9.81 \, \text{N}

Weight on the Moon: Fg,moon=m×gmoon=(1kg)×(9.81m/s26)=1.64NF_{g, \text{moon}} = m \times g_{\text{moon}} = (1 \, \text{kg}) \times \left( \frac{9.81 \, \text{m/s}^2}{6} \right) = 1.64 \, \text{N}

Interactive Charts

Weight - force and acceleration of gravity

Kg to lb converter

References