Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Mass is the amount of matter in an object, measured in kilograms (). It remains constant regardless of where the object is in the universe.
Weight is the force of gravity acting on an object, measured in Newtons (). It changes depending on the gravitational field strength of the location.
Gravity is an attractive force that acts between all objects with mass. The strength of this pull depends on the masses of the objects and the distance between them.
Gravitational Field Strength () represents the force per unit mass. On Earth, the value of is approximately (often rounded to in introductory problems).
On the Moon, the gravitational field strength is much weaker than on Earth, approximately .
Weight is a vector quantity because it has a direction (acting towards the center of the planet), while mass is a scalar quantity.
📐Formulae
💡Examples
Problem 1:
An apple has a mass of . Calculate its weight on Earth, assuming .
Solution:
Explanation:
To find the weight, we multiply the mass by the Earth's gravitational field strength.
Problem 2:
An astronaut has a mass of . What would be their mass and weight on the Moon, where ?
Solution:
Mass = . Weight:
Explanation:
Mass does not change regardless of location. The weight is calculated by multiplying the constant mass by the Moon's specific gravitational field strength.
Problem 3:
A robot weighs on Earth (). What is its mass?
Solution:
Explanation:
By rearranging the formula to , we can determine the mass from the weight and the gravitational field strength.