Topics
Gravitation
- Concept of Gravitation
- Force and Motion
- Centripetal Force
- Kepler’s Laws
- Law of Orbit or Kepler's First Law
- Law of Areas or Kepler's Second Law
- Law of Periods or Kepler's Third Law
- Newton's Universal Law of Gravitation
- Uniform Circular Motion (UCM)
- Earth’s Gravitational Force
- Earth’s Gravitational Acceleration
- Mass and Weight
- Gravitational Waves
- Free Fall
- Gravitational Potential Energy
- Escape Velocity
- Weightlessness in Space
Periodic Classification of Elements
- Classification of Elements
- Dobereiner’s Triads
- Newland's Law of Octaves
- Mendeleev’s Periodic Table
- Insights into Mendeleev’s Periodic Table
- Modern Periodic Law
- The Modern Periodic Table
- Structure of the Modern Periodic Table
- Modern Periodic Table and Electronic Configuration of Elements
- Groups and Electronic Configuration
- Periods and Electronic Configuration
- Periodic Trends in the Modern Periodic Table
- Atomic Size
- Metallic and Non-metallic Characters
- Gradation in Halogen Family
Chemical Reactions and Equations
- Chemical Reaction
- Chemical Equations
- Balancing Chemical Equation
- Types of Chemical Reactions > Combination Reaction
- Types of Chemical Reactions > Decomposition Reaction
- Types of Chemical Reactions > Single Displacement Reaction
- Types of Chemical Reactions > Double Displacement Reaction
- Endothermic and Exothermic Processes
- Rate of Chemical Reaction
- Factors Affecting the Rate of a Chemical Reaction
- Chemical Properties of Carbon Compounds > Oxidation
- Chemical Properties of Carbon Compounds > Reduction
- Corrosion of Metals
- Rancidity
Effects of Electric Current
- Electric Circuit
- Heating Effect of Electric Current
- Magnetic Effect of Electric Current
- Right-hand Thumb Rule
- Applications of Biot-Savart's Law > Magnetic Field at the Centre of a Circular Loop
- Applications of Ampere’s Circuital Law > Magnetic Field of a Long Straight Solenoid
- Force on a Current Carrying Conductor in a Magnetic Field
- Fleming’s Left Hand Rule
- Electric Motor
- Electromagnetic Induction
- Galvanometer
- Faraday's Laws of Electromagnetic Induction
- Fleming’s Right Hand Rule
- Alternating current (AC) and Direct Current (DC)
- Electric Generator
Heat
Refraction of Light
Lenses
- Concept of Lenses
- Images Formed by Convex Lenses
- Images Formed by Concave Lenses
- Sign Convention
- Lens Formula
- Magnification
- Power of a Lens
- Combination of Lenses
- The Human Eye
- Defects of Vision and Their Corrections > Myopia
- Defects of Vision and Their Corrections > Hypermetropia
- Defects of Vision and Their Corrections > Presbyopia
- Apparent Size of an Object
- Use of Concave Lenses
- Use of Convex Lenses
- Persistence of Vision
Metallurgy
- Physical Properties of Metals
- Physical Properties of Non-metal
- Chemical Properties of Metal
- Reactions of Metals
- Reactivity Series of Metals
- Chemical Properties of Non-metal
- Ionic Compounds
- Metallurgy
- Basic Principles of Metallurgy > Concentration of Ores
- Basic Principles of Metallurgy > Extraction of Metals
- Basic Principles of Metallurgy > Refining of Metals
- Corrosion of Metals
- Prevention of Corrosion
Carbon Compounds
- Bonds in Carbon Compounds
- Carbon: A Versatile Element
- Hydrocarbons
- Straight chains, Branched chains, and Rings of Carbon atoms
- Functional Groups in Carbon Compounds
- Homologous Series
- Nomenclature
- Chemical Properties of Carbon Compounds > Combustion
- Chemical Properties of Carbon Compounds > Oxidation
- Chemical Properties of Carbon Compounds > Addition Reaction
- Chemical Properties of Carbon Compounds > Substitution Reaction
- Ethanol
- Ethanoic Acid
- Macromolecules and Polymers
Space Missions
School of Elements
The Magic of Chemical Reactions
- Chemical Equations
- Types of Chemical Reactions > Combination Reaction
- Types of Chemical Reactions > Decomposition Reaction
- Types of Chemical Reactions > Single Displacement Reaction
- Types of Chemical Reactions > Double Displacement Reaction
- Chemical Properties of Carbon Compounds > Oxidation
- Types of Double Displacement: Neutralization Reaction
The Acid Base Chemistry
- Properties of Acids > Physical Properties
- The pH Scale
- Acids, Bases and Their Reactivity
- Acid or a Base in a Water Solution
- Preparation and Uses of Baking Soda
- Preparation and Uses of Bleaching Powder
- Preparation and Uses of Washing Soda
- Preparation and Uses of Plaster of Paris
- Chemicals from Common Salt - Soap as a Salt
The Electric Spark
All about Electromagnetism
- Magnetic force
- The Bar Magnet
- Right-hand Thumb Rule
- Applications of Biot-Savart's Law > Magnetic Field at the Centre of a Circular Loop
- Applications of Ampere’s Circuital Law > Magnetic Field of a Long Straight Solenoid
- Force on a Current Carrying Conductor in a Magnetic Field
- Electric Motor
- Electromagnetic Induction
- A.C. Generator
- Simple D.C. Motor
- Household Electrical Circuits
Wonders of Light 1
Wonders of Light 2
Striving for better Environment 1
- Abatement of Pollution
- Sustainable Use of Resources
- Definition: Mass
- Definition: Weight
Maharashtra State Board: Class 10
Definition: Mass
Mass is the amount of matter present in the object. The SI unit of mass is kg.
Maharashtra State Board: Class 10
Definition: Weight
The weight of an object is defined as the force with which the earth attracts the object.
Maharashtra State Board: Class 7
Mass and Weight:
1. Mass: It is the amount of matter in an object. It is related to inertia, which is the resistance of an object to change its state (whether at rest or moving). According to Newton’s first law, it is the measure of the inertia of an object. The greater the mass, the greater the inertia.
- Mass is a scalar quantity, meaning it only has magnitude, not direction. Mass does not change from one place to another; it stays the same everywhere.
- The SI unit of mass is kg. When using a two-pan balance in a shop, we are comparing the mass of two objects.
2. Weight: It is the gravitational force that the Earth exerts on an object. It depends on the mass of the object and gravity. Its S.I. unit is Newton.
- Weight is a vector quantity, meaning it has both magnitude and direction (towards the Earth’s centre).
- Weight can change from place to place, depending on the strength of gravity (for example, at different heights or on other planets). What we commonly measure in grams or kilograms is actually mass, not weight.
W = F = m × g .......( `g = (GM)/(R^2)`)
The weight of an object can change from one place to another, from one planet to another.
The weight of an object on the moon is given by the formula.
`"W"_"m" ="GM"_"m" xx "m"/"R"_"m"^2`
- Wm= weight of an object on moon
- Mm= mass of the moon = 7.36 × 1022
- Rm= radius of the moon = 1.74 × 106
- G = Universal Gravitational Constant = 6.67 × 10⁻¹¹ Nm2/kg2
- m = Mass of the object
Substituting the values:
`therefore` `"W"_"m" = (6.67 × 10⁻¹¹ xx 7.36 xx 10^22 xx"m")/((1.74 xx 10^6"m")^2)`
`"W"_"m" = 2.431 xx 10^10 "Gm"`
Similarly, the weight of the object on Earth is:
`"W"_"e" = 1.474 xx 10^11 "Gm"`
Taking the ratio:
`therefore` `"W"_"m"/"W"_"e" = ("Weight of object on Moon")/("Weight of object on Earth") = (2.431xx10^10"Gm")/(1.474 xx 10^11"Gm")= 1/6`
`therefore` Weight of an object on the moon is `1/6`th the weight of an object on the earth.
Maharashtra State Board: Class 10
Difference Between Mass and Weight:
| Aspect | Mass | Weight |
|---|---|---|
| Definition | Amount of matter in an object | Force exerted by gravity on an object’s mass |
| Symbol | m | W |
| SI Unit | Kilogram (kg) | Newton (N) |
| Measured With | Balance scale or beam balance | Spring balance |
| Depends On | Quantity of matter | Mass and gravitational acceleration (W = mg) |
| Varies with Location? | No | Yes |
| Constant on Earth & Moon? | Yes | No (less on Moon, more on planets with higher gravity) |
| Type of Quantity | Scalar | Vector (has direction towards the centre of gravity) |
| Can it be Zero? | No | Yes (in space or zero-gravity environment) |
| Example (Rajeev) | 75 kg (remains same everywhere) | 735 N on Earth (75 × 9.8), ~123 N on Moon |
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