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How To Calculate Weight In Physics

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Calculate The Lifting Weight

How To Calculate Weight in Physics
TL DR Summary
How do I calculate how much force is needed to lift a horizontal metal tube to a vertical position.

I will have a 25 foot long 3″ square tube inside the 25 foot long 4″ square tube. The weight of the 4″ square tube is 9.44lb/ft and the 3″ square tube is 6.88lb/ft .

coltonk said:This is for an antenna. The fulcrum is 5 foot from the bottom of the tube and the fulcrum is 5-1/2 foot about the ground. It has no counter-balance weight except for the 5 foot after the fulcrum.

berkeman said:If the fulcrum and ground supports can tolerate the extra weight of a counterweight at the bottom of the antenna mast, that would seem to be a big improvement in the forces required to raise the mast…

Let me see if I understand this correctly.

Baluncore said:The 25 foot long double tube weighs only 408 lbs.

mast truk  wireangle hgt tension deg   ft   lbs -16  0.0 1000.2 -15  0.3  984.8 -10  2.0  946.0 -5   3.8  906.2  0   5.5  865.5  5   7.2  823.8 10   9.0  781.1 15  10.7  737.5 20  12.3  692.9 25  14.0  647.5 30  15.5  601.1 35  17.0  554.0 40  18.4  506.2 45  19.6  457.8 50  20.8  408.8 55  21.9  359.4 60  22.8  309.6 65  23.6  259.5 70  24.3  209.3 75  24.8  159.1 80  25.2  109.0 85  25.4   58.4 90  25.5    0.0

Variables In The Weight Equation

The Weight Calculator uses the formula W = mg, or weight W is equal to mass m times gravity g. Note that the standard units for weight calculations are N, kg and m/s2. If you enter other units of measure for your calculation the calculator will do the units conversion for you.

Weight is a force and gravity can be thought of as an acceleration due to the pull of gravity. The equation W = mg is a special case of Newton’s second law of motion, F = ma, where force F equals mass m times acceleration a.

How To Get Weight From Mass

Weight and Mass are not the same physical quantity. They have different units and dimensions also. However, we can relate to them. In this article, Im going to explain how is weight different from Mass and how to get weight from the mass of an object. This article is basically for students of basic physics.

Measuring the Mass

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From Force And Acceleration

The property of mass is also understood as the measure of a physical objects resistance to being accelerated by the application of an external force. This concept of mass is sometimes referred to as inertial mass. Inertia is the tendency for a moving body to continue in a constant state of motion, so inertial mass is a measure of how much inertia a body has and how difficult it is to change its state of motion. The relationship between mass, force, and acceleration is expressed by Newtons second law of motion F=ma. This mathematical relationship tells us that, in the face of a constant force, a more massive body will accelerate more slowly. By measuring the force applied to a body and measuring the observed acceleration, we can calculate the mass of the body.

For example, say that we apply a 748 N force to a metal cube, and we measure its acceleration as 21m/s2. What is the mass of the metal cube? We can figure calculate the mass by dividing the magnitude of the force by the magnitude of acceleration so:


So we know that the metal cube must have a mass of 35.62 kg.

Why Do Objects Have Mass

Physics 2a

It has only been recently that scientists have begun to unlock the answer to why particles have mass at all. In the 1960s, several scientists noticed some problems with their equations describing the behavior of fundamental particles. Specifically, their equations predicted that certain particles generated during high-speed collisions would not have any mass. However, experimental observation indicated that these particles did, in fact, have a non-zero mass.

Scientists theorized that a bosons mass could be generated by the interaction between those bosons and an all-pervading field called the Higgs field . When massless bosons move against this field, their momentum is slowed, and they lose some energy. The Higgs field converts this energy into mass-energy, which manifests as the property mass that we measure. This interaction between the bosons and the Higgs field was predicted to create a new particle, a tiny boson dubbed the Higgs boson. The particle accelerator at CERN finally demonstrated the existence of the Higgs particle in 2013 and on October 8, 2013, Peter Higgs and François Englert were awarded the Nobel Prize in physics for their theoretical work on the particle.

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How To Calculate The Weight Of An Object

The weight of an object is the force of attraction that the object has to the Earth. It is the product of the mass of the object, multiplied by the acceleration due to gravity. You may choose to calculate the weight of an object to solve a physics problem. It is a basic calculation and it is often a fundamental step to solving other, more complicated problems. You can calculate the weight by identifying what given information you have, and putting the numbers into the designated equation.

Write down your given information for the weight problem. The problem will provide you with the mass of the object and the acceleration due to gravity. For example, the mass may be 3 g, and the acceleration due to gravity may be 9.81 meters per second per second.

Find the equation that needs to be used to solve the problem. The equation used to calculate the weight of an object is F = ma. “F” is the force in Newtons, “m” is the mass in grams and “a” is the acceleration due to gravity.

Put the values of the problem into the equation. For example, multiply the mass of the object times the acceleration due to gravity, or F=. You should receive an answer of 29.4 Newtons.

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Density To Weight Equation

So how do we calculate weight using density and volume? By rearranging the equation for density, which is defined as the mass per unit volume:

  • Density of the substance
  • m m Weight and
  • V V V Volume.

So if we know the density and volume of an object, we now know how to calculate its weight using density and volume.

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How To Calculate Weight From Mass

wikiHow is a wiki, similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 63 people, some anonymous, worked to edit and improve it over time.There are 8 references cited in this article, which can be found at the bottom of the page. This article has been viewed 1,174,131 times.Learn more…

The weight of an object is the force of gravity exerted on that object. The mass of an object is the amount of matter it has, and it stays the same wherever you are, regardless of gravity.XResearch source That’s why an object that has 20 kilograms of mass on earth also has 20 kilograms of mass while on the moon, even though it would only weigh 1/6 as much. It weighs 1/6 as much on the moon because the force of gravity on the moon is 1/6 of what it is on Earth. Read on for information about and tips on calculating weight from mass.

Example On Weight Formula

How to Calculate Weight in Physics : Physics Education

Example 1: The mass of the body is 50 kg. Calculate the weight using the weight formula. (Hint: use g = 9.8 m/s2.


To find the weight of the body.Mass = 50 kg Using the formula to find weight,W = mgW = 490 N

Answer: The weight of the body is 490 N

Example 2: If the weight of the body on the moon is 500N, find its mass. The value of g in the moon is 1.62 m/s2.


To find the mass of the body.Weight of the body on the moon = 500 N Using the formula to find weight,W = mgMass of the body = W/gMass of the body = 500/1.62Mass of the body = 308.64 kg

Answer: Mass of the body is 308.64 kg

Example 3: The mass of the body is 50 kg and the weight of the body is 490 N. With the help of the weight formula prove that g = 9.8 m/s2.


To prove, g = 9.8 m/s2 Weight of the body = 490 N Mass = 50 kg Using the formula to find weight,W = mg

Hence Proved g = 9.8 m/s2

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The English Engineering System

In the English Engineering system of units the primary dimensions are are force, mass, length, time and temperature. The units for force and mass are defined independently

  • the basic unit of mass is pound-mass
  • the unit of force is the pound alternatively pound-force .

In the EE system 1 lbf of force will give a mass of 1 lbm a standard acceleration of 32.17405 ft/s2.

Since the EE system operates with these units of force and mass, the Newton’s Second Law can be modified to

F = m a / gc


or transformed to weight

Fg = m ag / gc

The proportionality constant gc makes it possible to define suitable units for force and mass. We can transform to

1 lbf = / gc

gc = /

Since 1 lbf gives a mass of 1 lbm an acceleration of 32.17405 ft/s2 and a mass of 1 slug an acceleration of 1 ft/s2, then

1 slug = 32.17405 lbm

The mass of a car is 1644 kg. The weight can be calculated:

Fg =

= 16122.7 N

– there is a force of 16.1 kN between the car and the earth.

  • 1 kg gravitation force = 9.81 N = 2.20462 lbf

How To Use The Density To Weight Calculator

It’s pretty straightforward to use the density to weight calculator by following these steps:

  • Input the density of the material, making first sure that the unit is correct. You can change the units by clicking on the unit and selecting from a wide range of density units. For example, you know that the object is made of lead, so you would enter 11,340 kg/m³ as the density.

  • Enter the volume of space that the object occupies. If you don’t know the volume but do know the object’s dimensions, the advanced mode of the calculator allows you to enter the object’s length, width, and height. Let’s say the lead artifact is 250 cm³.

  • And that’s all there is to it. You now know the object’s weight, which in our example is 2.835 kg.

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    How To Calculate Tension In Physics

    This article was co-authored by Bess Ruff, MA. Bess Ruff is a Geography PhD student at Florida State University. She received her MA in Environmental Science and Management from the University of California, Santa Barbara in 2016. She has conducted survey work for marine spatial planning projects in the Caribbean and provided research support as a graduate fellow for the Sustainable Fisheries Group.There are 7 references cited in this article, which can be found at the bottom of the page.wikiHow marks an article as reader-approved once it receives enough positive feedback. This article has 16 testimonials from our readers, earning it our reader-approved status. This article has been viewed 1,825,179 times.

    In physics, tension is the force exerted by a rope, string, cable, or similar object on one or more objects. Anything pulled, hung, supported, or swung from a rope, string, cable, etc. is subject to the force of tension.XResearch source Like all forces, tension can accelerate objects or cause them to deform. Being able to calculate tension is an important skill not just for physics students but also for engineers and architects, who, to build safe buildings, must know whether the tension on a given rope or cable can withstand the strain caused by the weight of the object before yielding and breaking. See Step 1 to learn how to calculate tension in several physical systems.

    Acceleration Due To Gravity

    Weight = Mass X Gravity Worksheets

    Enter the acceleration due to gravity for your geographical location in metres per second per second or feet per second per second .

    The local gravity on earth is dependent on several factors such as latitude, height above sea-level, local geological density, etc refer to your national geological survey data for your location or use this local gravity calculator to determine a close approximation. The default value is set to 9.80665 ms-2 which is the standard acceleration due to earths gravity.

    You can also enter acceleration due to the pull of gravity for other places in the solar system such as , Moon , Titan or Europa for example.

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    Determining Tension On A Single Strand

  • 1Define the forces on either end of the strand. The tension in a given strand of string or rope is a result of the forces pulling on the rope from either end. As a reminder, force = mass × acceleration. Assuming the rope is stretched tightly, any change in acceleration or mass in objects the rope is supporting will cause a change in tension in the rope. Don’t forget the constant acceleration due to gravity – even if a system is at rest, its components are subject to this force. We can think of a tension in a given rope as T = + , where “g” is the acceleration due to gravity of any objects the rope is supporting and “a” is any other acceleration on any objects the rope is supporting.XResearch source
  • For the purposes of most physics problems, we assume ideal strings – in other words, that our rope, cable, etc. is thin, massless, and can’t be stretched or broken.
  • As an example, let’s consider a system where a weight hangs from a wooden beam via a single rope . Neither the weight nor the rope are moving – the entire system is at rest. Because of this, we know that, for the weight to be held in equilibrium, the tension force must equal the force of gravity on the weight. In other words, Tension = Force of gravity = m × g.
  • Assuming a 10 kg weight, then, the tension force is 10 kg × 9.8 m/s2 = 98 Newtons.
  • Ft = Fg + m × a
  • Ft = 98 + 10 kg × 1 m/s2
  • Ft = 108 Newtons.
  • Fc =10 × 2.67 = 26.7 Newtons.
  • So, our the total tension would be 98 + 26.7 = 124.7 Newtons.
  • T = 65.33 Newtons.
  • Differences Between Mass And Weight

    Here are some differences between these two physical quantities in tabular form

    SL. No.
    It gives the amount of matter in an object. It gives the force exerted by a body due to its mass.
    2 Mass is a Scalar quantity. Weight is a vector quantity.
    3 It is a fundamental physical quantity. It is a compound physical quantity.
    4 SI unit of Mass is Kilogram . SI unit of Weight is Newton .

    How is the mass different from the weight?

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    Weight Changes When Changes

    On Earth, your weight is caused by the earths pull on you. In a future lesson we will see that weight is the result of the your mass, the earths mass, and the distance between you and Earth.

    We will solve problems on this page using an average surface acceleration due to gravity

    • More massive interstellar objects have a higher surface acceleration due to gravity .
    • The higher the acceleration due to gravity the higher the weight

    Calculating Mass From Other Variables

    How To Calculate Weight The Weight Equation: Fw=mg

    Mass and length together give rise to an important variable called density. Volume, which is a measurement of a “chunk” of three-dimensional space, is derived from length units, and in the metric system, it has units of m3. Density is mass divided by volume and offers a sense of the “heaviness” of an object in relation to its size.

    Numerically, density = m/V and has SI units of kg/m3, though units such as g/cm3 are more common in science settings.

    • What is the mass of an 0.25-m3 object with a density of 2.5 kg/m3?

    Since = m/V, m = V. In this case, you have:

    = 0.625 kg.

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    Why Do We Measure Weight In Kg

    Since there is no practical easy way to measure mass, in everyday life we use the kilogram as a unit of weight assuming that the gravitational field is fairly constant around earth. However scales have to be calibrated locally to compensate the slight gravitational field variation in different places.

    Weight And Gravitational Force

    When an object is dropped, it accelerates toward the center of Earth. Newtons second law says that a net force on an object is responsible for its acceleration. If air resistance is negligible, the net force on a falling object is the gravitational force, commonly called its weight \overset , or its force due to gravity acting on an object of mass m. Weight can be denoted as a vector because it has a direction down is, by definition, the direction of gravity, and hence, weight is a downward force. The magnitude of weight is denoted as w. Galileo was instrumental in showing that, in the absence of air resistance, all objects fall with the same acceleration g. Using Galileos result and Newtons second law, we can derive an equation for weight.

    Consider an object with mass m falling toward Earth. It experiences only the downward force of gravity, which is the weight \overset . Newtons second law says that the magnitude of the net external force on an object is }_}=m\overset. We know that the acceleration of an object due to gravity is \overset, or \overset=\overset . Substituting these into Newtons second law gives us the following equations.


    The gravitational force on a mass is its weight. We can write this in vector form, where \overset is weight and m is mass, as

    In scalar form, we can write

    Since g=9.80\,}^ on Earth, the weight of a 1.00-kg object on Earth is 9.80 N:

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