Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Mass is defined as the quantity of matter contained in a body. It is a scalar quantity and remains constant everywhere in the universe.
The S.I. unit of mass is the kilogram (). For smaller masses, we use grams () and milligrams (). For larger masses, we use quintals and metric tonnes ().
Mass is measured using a beam balance or a physical balance. These instruments work on the principle of moments, where a horizontal beam indicates that the mass in the left pan is equal to the mass in the right pan.
Difference between Mass and Weight: Mass is the amount of matter (), while Weight () is the gravitational force acting on that matter. Mass is measured in , whereas weight is measured in Newtons ().
A physical balance is more sensitive than a common beam balance and is used in laboratories to measure mass accurately up to a milligram ().
📐Formulae
💡Examples
Problem 1:
A bag of sugar has a mass of . Calculate its mass in grams () and milligrams ().
Solution:
and
Explanation:
To convert to , multiply by : . To convert to , multiply by again: .
Problem 2:
An astronaut has a mass of on Earth. What will be his mass on the Moon, given that the Moon's gravity is th of Earth's gravity?
Solution:
Explanation:
Mass is an intrinsic property of a body and represents the quantity of matter. It does not change with a change in gravitational pull or location. Therefore, the mass remains .
Problem 3:
A truck is carrying of iron rods. Convert this mass into kilograms ().
Solution:
Explanation:
Since , we multiply the given value by . Thus, .