Units and Measurement

Unit of Weight

When you buy a kg of onion, we generally assume that ‘1 Kg’ refers to its weight. But if we go by the principal definitions of Physics, mass and acceleration combined results in weight. Basically, if we assume the acceleration is 10m/s, therefore the mass is 100 grams. Hence, have you purchased 100 grams of onion, or is it 1 kg of onion? The entire logistics in relation to the relevance of the actual unit to represent the unit 1 kg is where the Unit of Weight comes into play.

unit of weight

Unit Of Weight

Introduction to Unit of Weight

If we think in a practical sense, then weight represents how heavy or light an object is, irrelevant of its size and shape. Identifying if the object is heavy or light is also practically an easy job. However, when it comes to calculating the exact weight of an object, the practical reference of light and heavy becomes objectionable.

For instance, 1kg of cotton may seem much lighter in weight than 1 kg of solid rock. This is where the confusion arises further. The numerical value of an object, when calculated based on the principal of Unit of weight, can have a different interpretation.

Application of Unit of Measurement of Weight and Mass

Units of Measurement is generally based on the most commonly used 4 types of recognized system.

  1. CGS System – Also known as Centimeter, gram, and second system
  2. MKS system – Also known as Meter, kilogram, and second system
  3. FPS system – Also known as Foot, Pound, and Second system
  4. SI Unit System – Also known as Internation system of Units

As of 1956, SI unit System is the most used and recognized standard unit of measurement. It consists of seven basic units of Measurement. They are – 

  1. meter (m) for Distance
  2. kilogram (kg) for Mass
  3. Second (s) for time
  4. Kelvin (K) for Temperature
  5. Ampere (A) for Electric Current
  6. Mole (mol) for Amount of substance
  7. Candela (cd) for Luminous Intensity

Understanding Weight

Weight can be defined as the force at which the gravitational field pulls an object towards the earth’s surface.

We all know that the centre of gravity has a specific force that attracts all the objects towards it. Unit of weight is the numerical representation of how much force is required to force an object to reach the earth’s surface.

  • The SI unit of Weight

Supposing you have a piece of wood that has a precalculated mass of 1 kg and it falls on the ground with a gravitational force of 1 meter per second squared.

As we know that weight is equal to the product of mass and gravity, so in this case

W = 1 kg (mass) X 1 mtr/sec sq (force of gravity)

Hence the weight of the wood is 1 kg/mt/ sec sq.

In a simplified version, the SI unit of weight of kg/mt/sq sq. is called Newton (N), with respect to the scientist who discovered it.

  • Alternate Units of Weight 
  1. Dimensional Unit of Weight –  The dimensional Unit of Weight is calculated as the product of mass, distance, and time. 

Hence the Dimensional Unit of weight (W) = Mass (M) X Distance (L) X Time (t sq) 

2. CGS unit of Weight – Represented with the scientific term Dyne, it is implied in terms of the product of centimetre gram and seconds. Hence the numerical representation is 1 gram cm second sq.

1 Newton divided by 10,000 is equivalent to 1 Dyne

3. Base Unit of Weight – This unit of weight has the same value as that of the SI unit of weight.

Various other units of weights also used includes gram, slug, pound-force, etc.

Metric Conversion of Units of Weight

Gram is one of the most universally accepted units of weight. The conversion of a gram to kilogram is based on the standard denominations as mentioned below:

1 g = 0.001 kg

1 mg = 0.000001 kg = 0.001 g

Further, 1 centigram = 0.00001 kg = 0.01 g

1 metric ton = 1000 kg

Understanding Mass 

Mass is defined as the measurement of the matter within an object. Mass and weight have different values, but they are often confused as the same. It is called the quantitative measurement of inertia

Unlike weight, the mass has a constant value that is not affected by the gravitational changes. It is represented in form of a kilogram or gram. Therefore if a body has a mass of 70 kg on planet earth, it will remain the same even on the moon, regardless of the presence or absence of Gravitational pull.

Relationship between Mass and Weight

Based on Newton’s 2nd law of Gravitation force (F) is equal to the product of the mass (M) and the rate of acceleration (A)

F= MA

Even if the mass remains unchanged, the weight is altered based n the gravitational changes. Hence the weight of a person on earth and on the surface of the moon will greatly vary.

FAQ on Unit of Weight

Question 1: What is Weight?

Answer 1: Weight can be defined as the force at which the gravitational field pulls an object towards the earth’s surface.

Question 2: What is the SI uni of weight and Base Unit of Weight?

Answer 2: SI unit of weight is Newton which is also represented in terms of kg m s.square. The Base unit of Weight is also represented as kg m s.sq

Kg represents kilogram, m represents meter and s represents second (second square root in Unit of weight)

Question 3: What is the difference between mass and weight?

Answer 3:

Mass Weight
The amount of matter within an object is defined as Mass. The force with which an object is pulled towards the centre of gravity is termed as weight
It is represented with the term Kilogram (Kg) or Gram (g). It is represented with the term Newton (N)
It is a scalar quantity as it has only magnitude but no direction It is a vector quantity as it has both direction and magnitude.
Mass is constant in value regardless of the gravitational forces Gravitational changes alter the weight based on the increasing or decreasing force.
Mass can never be zero as gravitational force fields do not hold any relevance to the mass of a body. Weight can be zero when there is no gravitational force.
Measured using beam balance, calibrated balance or analytical balance. Spring balance or compression balance is used to measure weight.
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