Review the key concepts, formulae, and examples before starting your quiz.
πConcepts
A force is defined as a push or a pull acting upon an object resulting from the object's interaction with another object. Force is measured in Newtons ().
Force is a vector quantity, meaning it has both a magnitude (size) and a specific direction. It can change an object's speed, direction, or shape.
The instrument used to measure force is called a Newton meter or a spring balance. It works based on the principle that the stretch of the internal spring is proportional to the force applied.
Mass () is the amount of matter in an object and is measured in kilograms (), whereas Weight () is the force of gravity acting on that mass and is measured in Newtons ().
Gravitational field strength () represents the force of gravity per unit mass. On Earth, , though it is often rounded to for introductory calculations.
Balanced forces occur when the resultant force is , meaning the object remains at rest or continues at a constant velocity. Unbalanced forces cause acceleration.
πFormulae
π‘Examples
Problem 1:
Calculate the weight of a science textbook with a mass of on Earth, where the gravitational field strength is .
Solution:
Explanation:
To find the weight, we multiply the mass of the object by the acceleration due to gravity (). The resulting unit is Newtons ().
Problem 2:
An astronaut weighs on the Moon, where the gravity is . What is the astronaut's mass?
Solution:
Explanation:
By rearranging the formula to solve for mass, we divide the weight by the local gravitational field strength. Mass remains constant regardless of location.
Problem 3:
A spring in a Newton meter has a spring constant of . If the spring extends by when an object is hung from it, what is the force being measured?
Solution:
Explanation:
Using Hooke's Law, the force exerted is the product of the spring constant and the extension of the spring.