Sunday, July 14, 2024

What Is Mg In Physics

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Weight And Mass On The Moon

Using W=mg to Calculate Weight I | Physics

The value for gm is approximately 1/6 of the value for g on Earth. Thus, an object on the Moon would weigh about 1/6 of its weight on Earth.

Using a spring scale, if you weigh 60 kg on the Earth, you would weigh only 10 kg on the Moon. However, using a balance scale on both Earth and the Moon, your mass would be the same.

Measuring Units For Rf Radiation

Remember that RF radiation is wifi signals and Bluetooth signals. These wireless technologies impact our cells by heating them up a little bit and they also impact us on a biological level.

RF radiation always has a frequency. This is also why you have to set your old radio to a certain frequency in order to pick up a signal. However, when we measure the strength of the radiation we dont look at the frequency. Instead, we are more concerned with how much the radiation impacts the surface it touches.

When the RF radiation causes an electric current on the surface it reaches.

This is also why people who are hypersensitive to electromagnetic radiation can literally feel the radiation. My wife explains it like a buzzing sensation on the skin.

When Does Normal Force Equal To $mg$

Can someone once and for all explain when does normal force equal to mg?

I know for sure that when there is no friction, normal force will be equal to mg.But, i encountered some questions when there is some mass on an incline with friction, and then the normal force was the y component of mg.

It does not make sense to me, because as i understood when there is friction, we cannot assume that mg will be equal to normal force.

Normal Force arises due to the Newton’s Third law. Normal Force will be always acting opposite to the force falling on the surface.Normal Force is a reaction force. Remember

Normal force is equal to mg only when the object is placed horizontally, and the force is acting in the direction of the gravitational field.

Now your second question

Here you will see that the weight of the body is passing through the Centre of gravity and acting in direction of the centre of the earth.

But the component of weight on the incline is not mg it is cos component.In order to satisfy the Newton’s third law Normal reaction to the object is the cos component$$N=Wg\cos \theta$$ even if friction is there or not there this will be the same

Normal force $F_N$ is just the force between two surfaces. It’s called “normal” because it acts perpendicular to the surfaces.

Gravitational force is completely unrelated. Gravity always acts with $F_g = -mg$. The minus sign indicates that the force points down.

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Volts Per Meter Explained

The easiest way to measure and understand RF radiation is to stick to volts per meter . Its typically easier to understand than microWatts per square meter .

In all our examples on this website, I also stick to V/m when I talk about RF radiation. This just keeps things easier to understand and work with. I like this measuring unit as it is easier to explain and understand than the other alternatives. At least if you ask me. If you have a degree in physics or engineering you might prefer to use µW/m² but for the rest of us, I think we should at least start with V/m.

When we talk about V/m we are looking at how intense the electromagnetic fields is that is created by the radio frequency.

When we measure an RV signal of 1 V/m we are dealing with a signal where theres 1 Volt difference between two points that are 1 meter apart.

Conversion From Mass To Weight

Physics Formula W=mg

Newton’s second law is used to convert between weight and mass:

The equation for force is F = ma .

Here, F is the force due to gravity , m is the mass of the object in question, and a is the acceleration due to gravity, on Earth approximately 9.8 m/s² or 32.2 ft/s²).

In this context the same equation is often written as W = mg, with W standing for weight, and g for the acceleration due to gravity.

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Acceleration Due To Gravity

The acceleration due to the force of gravity on Earth is designated by g. Its value is:

g = 9.807 meters per second-squared in the metric or SI system of measurement

g = 32.2 feet per second-squared in the English system of measurement

Note: Since most textbooks use g = 9.8 m/s2 and 32 ft/s2, we will also use the rounded-off version in these lessons.

In the equation F = mg, you must use the same measurement system for mass, m, as you do for g.

Note: Some textbooks carelessly define g as the acceleration of gravity. That is incorrect and misleading, since gravity does not accelerate. The expression should be the acceleration due to gravity, which is correct description of g.

Care must be taken in defining scientific terms.

What Are The Standard Units For Measuring Emf Radiation

The problem with measuring EMF radiation is that we havent defined any standards yet. Some EMF meters will use one set of units while the next will measure the same things with a completely new set of units.

Hopefully, this article will help you get clarity and understand the basic units we use and how to convert from one to the other.

Before we dive into the units we need to make sure we know the three most popular types of EMF:

  • RF radiationRF stands for Radio Frequencies and this is the type of radiation we find around wifi, smartphones, laptops, tablets, cell towers, Bluetooth, and much more. You can check out our beginners guide to RF radiation here.
  • Magnetic fields Magnetic fields are different. They are closely related to the electric fields we look at below. Magnetic and electric fields always appear together and they are always there when we have electricity. They form around electric cords, power lines, generators, chargers for electric devices, etc.Magnetic fields and electric fields are what we call ELF radiation. ELF stands for Extremely Low Frequencies and we have a great guide to ELF here for beginners.
  • Now you should know that we are dealing with three different types of EMF radiation. Thats important to understand before we can proceed to take a look at how we measure the level of each type of radiation.

    Here are the different ways we measure each type of EMF:

    EMF Type
    milliGauss , nanoTesla , Ampere per meter
    Electric Fields Volts per meter ,

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    Emf Units Explained: V/m Milligauss W/m Etc

    Welcome to the world of weird names and confusing units. The physics behind EMF radiation can easily get to your head when you are new to this stuff. But stick with me for a few minutes here and everything should start clearing up!

    In this article, I will explain to you exactly how we measure EMF radiation.We will do this from a beginners level in plain English!

    Lets get started!

    Its really important to understand these different measuring units because they can get really confusing when you are trying to compare two different numbers.

    This Meter Is Great If You Struggle With The Measuring Units

    Inclined plane mgsin(theta)

    As I mentioned above, its easy to mix up the different measuring units. This is because we are dealing with different types of EMF radiation and we are also dealing with more than one ways to measure the radiation of the same type.

    This is where this specific EMF meter is really brilliant!

    As you can see from the picture above, theres a scale mounted on the far right side of the screen. It will show you immediately if you are in the green zone, the yellow zone, or in the red zone.

    This range is calibrated according to the recommendations among building biologists.

    Luckily, building biologists are agreeing on these limits. They might be using different measuring units, but they are able to convert between the two and still talk about the same limit.

    This is why you can always see an indication of whether you are measuring high toxic levels or if the radiation you are measuring is within the recommended limits. This makes everything so much easier because you dont have to think about the many different measuring units.

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    Inertial Vs Gravitational Mass

    Although inertial mass, passive gravitational mass and active gravitational mass are conceptually distinct, no experiment has ever unambiguously demonstrated any difference between them. In classical mechanics, Newton’s third law implies that active and passive gravitational mass must always be identical , but the classical theory offers no compelling reason why the gravitational mass has to equal the inertial mass. That it does is merely an empirical fact.

    Albert Einstein developed his general theory of relativity starting with the assumption that the inertial and passive gravitational masses are the same. This is known as the equivalence principle.

    The particular equivalence often referred to as the “Galilean equivalence principle” or the “weak equivalence principle” has the most important consequence for freely falling objects. Suppose an object has inertial and gravitational masses m and M, respectively. If the only force acting on the object comes from a gravitational field g, the force on the object is:


    This says that the ratio of gravitational to inertial mass of any object is equal to some constant Kif and only if all objects fall at the same rate in a given gravitational field. This phenomenon is referred to as the “universality of free-fall”. In addition, the constant K can be taken as 1 by defining our units appropriately.

    Newtons Laws Of Motion

    • Explain the difference between mass and weight
    • Explain why falling objects on Earth are never truly in free fall
    • Describe the concept of weightlessness

    Mass and weight are often used interchangeably in everyday conversation. For example, our medical records often show our weight in kilograms but never in the correct units of newtons. In physics, however, there is an important distinction. Weight is the pull of Earth on an object. It depends on the distance from the center of Earth. Unlike weight, mass does not vary with location. The mass of an object is the same on Earth, in orbit, or on the surface of the Moon.

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    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:

    Value Of G Calculation And Equation

    Model of magnesium atom stock vector. Illustration of mass

    Value of g in fps

    The acceleration felt by a free-falling object due to the gravitational force of the mass body is called gravitational acceleration and is expressed by g calculated using SI unit m/s2. The value of g depends on the mass of the body and its size, and its value varies from body to body. The value of g on the moon is constant.

    Acceleration Due to the Gravity of the Moon

    The acceleration due to the gravity of the moon or the magnitude of g on the moon is 1,625 m/s2.

    Calculate the acceleration due to the gravity of the moon

    The acceleration due to the formula of gravity is indicated by

    G = GM / R2

    • G is the universal gravitational constant, G = 6.674 x 10-11 m3 kg-1 s-2.

    • M is the mass of the body measured using kg.

    • R is the mass body radius measured by m.

    • g is the acceleration due to the gravity determined by m/s2.

    The mass of the moon is 7.35 × 1022Kg.

    The radius of the moon is 1.74×106m

    Substituting the values in the formula we get-

    g= 6.67×1011 × 7.35 × 1022 / 2

    Thus, the value of g on the moon is g=1.625m/s2.

    The Acceleration Due to Gravity also Follows the Unit of Acceleration

    Newton’s Law of Gravitation as applied to the Earth is F = G m M / r2, where F is the gravitational force acting on the body of mass m, G is the universal gravitational constant, M is the mass of the Moon, and r is the distance of the body from the centre of the Sun. g is the factor in equation F = m g, so g is given as follows:

    g = G M / r2

    There are two consequences of this:

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    Difference Between Mass And Weight

    Mass is the amount of matter present in a body while weight is a measure of how strongly gravity pulls on that matter. Mass is an intrinsic property of the body and remains the same wherever the body might be. Weight is a force, and force is . The weight of an object is its mass times the acceleration due to gravity. The weight of the body differs by place. For example, objects weigh less on the moon where gravity is lower compared to the Earth.

    Measurement Of Mass Vs Weight

    Weight is measured using a scale which effectively measures the pull on the mass exerted by the gravity of the earth. Mass of a body is measured by balancing it equally with another known amount of mass. Mass may be measured using a pan balance while Weight may be measured using a spring balance. Methods may be interchanged if gravity is known and constant, as it is on earth.

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    Do I Really Need An Emf Meter

    The short answer is yes.

    Theres simply no other ways to know how much radiation you have in your home.

    It is possible to find information online where people have tested different types of electronic devices and appliances, but you need to do your own testing. This is because each brand and model of an electronic device will emit its own level of radiation. Two routers from the same brand can emit totally different RF radiation values.

    We have also done a ton of testing with our EMF meter and if you want to see some of the numbers from our house you can check out these two articles:

    The Contact Camp’s Definition Of Weight

    Error Using mgh – Intro to Physics

    Any time we “feel” our weight, we are invariably in contact with another surface. That surface mightbe the ground or a chair or a reclining astronaut’s seat, and we might be sitting on the beach or acceleratingin a rocket. That inspires the Contact Camp’s definition of weight, which is “An object’s weight is thecontact force exerted on it by whatever is supporting it, in any situation.” Your weight as defined thisway is what is measured by an ordinary set of weighing scales placed between you and whatever is pushing onyou . When standing on Earth, your weight won’t quite equal the pull of gravity onyou unless you are standing at either the North or South Pole.

    In the picture at left, Earth pulls on the mass m with a force mg, and the table supports the mass with the contact force labelled “weight”. Applying Newton’s “F = ma” here gives

    mg weight = m× acceleration.


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    Example: How Much Force To Hold An Apple With A Mass Of 01 Kg

    F = mg

    F = 0.1 kg × 9.8 m/s2

    F = 0.98 kg m/s2

    Force is measured in Newtons which are the same as kg m/s2

    F = 0.98 N

    So it needs a force of about 1 Newton to hold up an apple.

    We also say the apple has a weight of 0.98 N.

    To convert a mass in kg to a force in Newtons multiply by 9.8 m/s2

    Another example:

    Microwatts Per Square Meter Explained

    We can also measure the strength of our RF radiation with µW/m²

    Instead of microWatts per square meter , we could just as well use W/m2 but we would get REALLY low numbers.

    1 W/m² = 1000,000 µW/m²1 W/cm² = 10,000 W/m²

    But these are all the same thing.

    We are measuring the effect in Watt on a specific surface area . instead of looking at the difference in Volts between two points we are measuring what we call the power flux density.

    This basically means that we measure the power of the radiation as an average over time.

    For that reason, we also prefer V/m where we can get better readings on RF radiation that may spike all of a sudden. This is very typical for Bluetooth and Wifi signals. Our smart meters, phones, laptops, routers, etc. will typically send outbursts of radiations all of a sudden and they go back to a lower intensity.

    We will leave the µW/m² unit for now and stick to V/m.

    But now you know that you can also measure RF radiation with µW/m² and you also know that its a little more complicated to use than V/m.

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