9.4 Weight

Description

Quick Overview

This section explains the concepts of weight, its dependence on mass and gravitational acceleration, and how weight varies between different celestial bodies.

Standard

Weight is defined as the gravitational force that the Earth exerts on an object. It depends on the mass of the object and the acceleration due to gravity, which varies by location. The section also elaborates on how weight on the Moon is significantly less than on Earth due to the Moon's lower gravitational force.

Detailed

Weight

Weight is the force exerted on an object by gravity, influenced by its mass and the gravitational acceleration acting upon it. As stated, the formula for weight is given by

W = m Ɨ g,

where W is weight, m is mass, and g is the acceleration due to gravity.

When studying gravitation, it's essential to recognize that while an object's mass remains constant, its weight can vary depending on the gravitational pull at different locations. For example, the weight of an object on the Moon is only about one-sixth of its weight on Earth, which can be calculated as W_m = (1/6) Ɨ W_e. The section further detailed the relationship between weight, mass, and gravitational forces on celestial bodies, emphasizing that weight is a vector quantity acting downwards. Understanding these concepts is crucial for comprehending the broader phenomena of gravitational interactions.

Key Concepts

  • Weight: The gravitational force acting on an object, calculated as W = m Ɨ g.

  • Mass: The quantity of matter in an object which remains constant regardless of location.

  • Gravitational Acceleration: The acceleration due to gravitational pull, varying based on location.

Memory Aids

šŸŽµ Rhymes Time

  • Weight is mass times g, gravity pulls down, that's the key.

šŸ“– Fascinating Stories

  • Imagine an astronaut who weighs 180 N on Earth. When they visit the Moon, they wonder, 'Why do I feel so light?' They check and discover, their weight is now just 30 N due to the weak Moon gravity!

šŸ§  Other Memory Gems

  • To remember the weight formula, think: 'Weight is mass multiplied by gravity, W = m Ɨ g!'

šŸŽÆ Super Acronyms

MGW

  • Mass Generates Weight - the higher the mass
  • the greater the weight!

Examples

  • A 10 kg object on Earth has a weight of 98 N due to gravitational acceleration of 9.8 m/sĀ².

  • On the Moon, the same 10 kg object would weigh only 16 N, as the gravitational acceleration is about 1.6 m/sĀ².

Glossary of Terms

  • Term: Weight

    Definition:

    The force exerted by gravity on an object, dependent on its mass and the gravitational acceleration.

  • Term: Mass

    Definition:

    A measure of the amount of matter in an object, which remains constant regardless of location.

  • Term: Gravitational Acceleration

    Definition:

    The acceleration experienced by an object due to the gravitational attraction of a celestial body.

  • Term: Gravity

    Definition:

    The force by which a planet or other celestial body attracts objects towards its center.