Mass and Weight: Measurement

Understanding Mass and Weight

Mass and weight are two different concepts in physics, often confused. Here's how they differ:

• Mass is the amount of matter in an object, measured in kilograms (kg). It remains constant regardless of location.
• Weight is the force exerted by gravity on an object, measured in newtons (N). It can change based on the gravitational field strength.

 

Measuring Mass

Mass is measured using balances. Here are some common types:

• Lever Balance: Uses a pivot and lever arms to compare an unknown mass with a known mass.
• Chemical/Beam Balance: A precise instrument used in laboratories to measure small masses.

 

Measuring Weight

Weight is measured using a spring balance. Here's how it works:

• Spring Balance: Measures weight based on the extension of a spring. The extension is proportional to the weight applied, according to Hooke's Law: $$F = k \cdot x$$ where $F$ is the force (weight), $k$ is the spring constant, and $x$ is the extension of the spring.

 

Worked Example