Weight Calculator
Calculate weight from mass and gravitational field strength.
Formula first
Overview
Weight is the measure of the gravitational force acting on an object's mass, specifically defined as the product of mass and local gravitational acceleration. Unlike mass, which is a scalar and intrinsic property of matter, weight is a vector quantity that varies depending on the strength of the surrounding gravitational field.
Symbols
Variables
m = Mass, g = Gravitational Field Strength, W = Weight
Apply it well
When To Use
When to use: Use this equation when calculating the downward force an object exerts on a support or the force it experiences due to a planet's gravity. It assumes the object is in a region where the gravitational field strength is known and relatively uniform.
Why it matters: Understanding weight is essential for structural engineering, where load-bearing capacities must exceed the weight of materials, and for aerospace, where engines must overcome weight to achieve lift. It clarifies the distinction between an object's physical quantity of matter and the external force pulling on it.
Avoid these traps
Common Mistakes
- Confusing mass (kg) and weight (N).
- Using g=10 without checking question.
One free problem
Practice Problem
A scientific rover on the surface of Mars has a mass of 150 kg. If the gravitational acceleration on Mars is 3.7 m/s², what is the rover's weight on the Martian surface?
Solve for:
Hint: Multiply the mass of the rover by the Martian gravitational acceleration.
The full worked solution stays in the interactive walkthrough.
References
Sources
- Halliday, Resnick, Walker, Fundamentals of Physics
- Britannica: Weight (physics)
- Wikipedia: Weight (physics)
- Halliday, Resnick, Walker, *Fundamentals of Physics*
- Bird, Stewart, Lightfoot, *Transport Phenomena*
- Wikipedia: Newton (unit)
- Halliday, Resnick, Walker, Fundamentals of Physics, 11th Edition
- Britannica, The Editors of Encyclopaedia. 'Weight'. Encyclopedia Britannica, 20 Jul. 2023.