# Questions tagged [weight]

Weight is the force on the object due to gravity. DO NOT USE weight as a colloquial substitute for mass.

260 questions
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### Measuring weight with weighing scale doing dumbbells

I am on a weighing scale that measures 'weight' (not mass). And I'm performing bicep curls with two 5Kg dumbbells in each hand. The body is kept straight during the same. I was asked to plot the ...
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### The Effect of Movement on Readings of a Scale

I am holding a book in my hand and standing on a scale, the scale reads X Newtons. Then at t=1 second, I start to move the book, and by t=2 seconds, the book is at rest 0.5 m higher than its initial ...
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### The helium balloon and buoyancy

Well I noticed something with a helium balloon which a little weight was tied to its rope to avoid it flying away. When the weight is on the ground and the rope is taut, I pulled it down a little and ...
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### How can buoyancy lift an object if the object is resting on the bottom? [duplicate]

The situation I am thinking about is that, for example, lets say that there is a block that weighs 10N outside of water, when it is put into water its apparent weight is 2N. From this it can be ...
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### Weight of objects

I recently observed that on a weighing machine(rectangular) a object weighed the same as the half portion of the same object with it's other half hanging out of the boundary of the machine (The ...
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### Using car weight in parking ramps to create energy [closed]

What if... large parking ramps had an optional car elevator on the upper floors that allowed drivers the option of using that to descend to the ground level. As your car goes down the empty counter ...
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### Is the weight of an object moving at escape velocity equal zero?

If an object would be accelerated to the escape velocity would it's weight be equal to zero? Say I throw a ball from Earths surface (assuming frictionless atmosphere) upwards at 11.186km/s is it's ...
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### How does terminal velocity affect the weight of a closed system? [duplicate]

Conducting a little hypothetical experiment here that I do not have all of the equipment to physically conduct, let's say that one uses a toy plastic solider like this ... as well as a sealable ...
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### Mass versus Weight [duplicate]

What are the difference between mass and weight? I keep getting confused in my physics class, and I am in 8th grade. Thank you in advance.
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### What happens to your weight when you go a specific height above the surface of the earth?

How would you use the Universal Gravitation equation $F=\frac{Gm_1m_2}{r^2}$ to calculate the weight of a person at a specific height above the earth? If, for example, you were 6370m above the earth ...
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### P.E. and weight of object in constant speed [closed]

If an object from rest is lifted up in the air by putting it into palm with constant speed $v$ what is its kinetic and potential energy of that object? As the object moving with constant speed (no ...
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### Show that the weight of an object suspended from two other objects is equal to the sum of the vertical components of the two weights [closed]

The following shows a mass with weight $M$ suspended from two other masses, labelled $m$ The system is in equilibrium, and the question following from this diagram is to show that $M=2m\cos\theta$...
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### Weight in system involving center of mass

A block of mass $m$ is attached to a string and suspended inside a hollow box of mass $M$. The box rests on a scale that measures the system's weight. If the string breaks, does the reading on the ...
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### Does a weight and force of same magnitude on a pulley make any difference?

I am confronting a confusion here.Here it goes. Imagine a single fixed pulley system with one end of the rope attached to a mass m. If you pull the other end with a force 2mg ,the mass will have a ...
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### Why is 1 newton meter=.225 lbs force?

This is a general question regarding force (mass x acceleration). I understand 1N =1kg mass x 1 m per second sq) all this basically tells me is that the force is proportionally increased and ...
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### What Does a Balance Scale Weigh?

This is, I feel sure, a question I'll eventually be embarrassed about having had to ask, but: Here is a picture of a balance scale. The black rectangle is a vacuum caused by an incredible coincidence ...
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### No water from hole of the cup because of weightlessness?

Let's say I have cup with water, but with a little hole in the bottom of cup somewhere Galileo worked out that if you just let something fall, it will accelerate towards the ground at the same rate ...
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### Torricelli's law during freely falling cup

How Torricelli's law can be applied to freely falling cup with a hole? It has been observed that in the free fall of the cup there will be no water coming out of the hole. But why? Torricelli's law ...
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### Weightlessness under free fall? [closed]

What are the possible ways of showing that freely falling objects has no weight in normal life and in laboratories?
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### How much weight can be supported by the air blown from a hair dryer? [closed]

How much weight can be supported/levitated by the air blown from a typical hairdryer? For example, when you place a piece of paper over it, it usually floats, but the same won't happen for a car.
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### What is the 'weight' (not mass!) of the Earth?

I am asking what might be the weight (not mass!) of the earth. My weight is the amount of force exerted on me by Earth (say 600N). So, weight of earth should be amount of force exerted on Earth by me (...
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### Apparent weight of an empty balloon vs apparent weight of a balloon filled with air [duplicate]

If the same sensitive spring balance weighs (in air) a balloon when empty (W1) and when filled with air (W2), which reading will be greater and why?
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### Unit of weight and mass [duplicate]

Doctor asked me how much did I weigh. Should I say it is "50 kg" or "500 N" ? Though the unit of weight is Newton, I have seen people mentioning their weight only in terms of Kilogram. Why is it so?
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### Joules in zero-gravity in space

I started studying physics recently and I got a question. So newtons are the force that mass exerts when it moves. let's suppose I have a ball that weighs 5 kg. On earth, this ball would weigh 49N ...
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### If falling from height into water, at what height would a buoyancy aid be more likely to cause injury?

There are strict requirements for lifejacket / buoyancy aids in the offshore oil & gas industry, requiring them to be worn when working above the water. Some places have been noted to be using a ...
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### weight of a canister of air

Consider four scenarios: (on a typical weighing scale) Measure the weight of a canister of air filled at atm pressure Measure the weight of a compressed canister of air Measure the weight of a ...
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### Acceleration Due To Gravity When Finding The Weight Of An Object

$W=mg$ When finding the weight of an object, why do we multiply the mass of the object by the acceleration do to gravity $g$ even though the object isn't moving downwards?
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### How many Newtons are in a kg exactly?

I understand that it is supposed to equal the gravity coefficient, which is defined as exactly 9.80665. But when i search google i saw one result saying 9.80665002864, and at first i thought it may ...
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### Is it possible to crush something with balloons

Imagine an average party balloon. Little rubber ball you can inflate with a few breaths. If you had a box of deflated balloons that weighed a ton, and you dropped it on something, it would be crushed. ...
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### The weight of something in a specific gravity field [closed]

I am working on a project in my free time and need to know what the weight of a person who has a mass of 70 kg in a gravitational environment of 0.1035773536599592926 pound-force would be.
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### Why isn't the apparent weight of a body in a fluid equal to the buoyant force? Why does buoyancy reduce it instead?

I have been very confused about this for some time now. We know that when an elevator accelerates upward, the apparent weight of a body placed inside it equals the normal force exerted by the elevator ...
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### Does weight affect the Earth's magnetic field?

Does the weight of a city influence the earths magnetic field, sort of like you can crush a magnet by putting more weight on the magnet then it can handle, for example an extremely heavy hammer?
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### Demystifying the physics of weightlessness in parabolic flights

Parabolic flights are often described roughly as a plane accelerating upward for a certain time and then free falling (thus stopping its thrust) and during the arc-path it takes before falling ...
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### What would a regular bathroom scale indicate as it's sinking underwater

It seems intuitive that a (waterproofed) spring-based scale placed at the bottom of a lake would indicate the weight of the water column above it. But assume the scale sinks from the surface of the ...
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### does the weight of a beaker of water increase or decrease when a submerged ping-pong ball is released? [closed]

if a beaker was filled with 200 cc of water and we tethered a ping pong ball to it's floor and that ping pong ball size is 10 cc . Q1: what will be the weight of the beaker at that time ? (ignore ...
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### Apparent weight and true weight

I want to know what do we actually measure in a weight machine, true weight or apparent weight? Please help me in understanding this concept.
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### changing force without mass or acceleration alteration

A water tank put on scale measuring $50 kg$ , inside the tank a fully submerged balloon tied with a thread to the tank bottom. If the thread was cut, will there be a different reading on the scale ...
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### How to predict the weight of helium?

I have a balloon, which weighs 10 grams. now i fill it with helium (x gram)... since I added helium into the balloon. now the weight should be 10+x grams... but the balloon goes upwards. Shape of the ...
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### What is the true nature of weightlessness?

Suppose you are in an elevator and you and the elevator free-fall under the influence of gravity, you feel weightlessness. This weightlessness is because the Normal Force due to the elevator is $0$ N. ...
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### Can you add helium to an already inflated soccer ball to make it lighter?

I was in a meeting today and a scenario was presented that began with two soccer balls of identical weight (both inflated). One of the balls then had helium added to it, and became heavier in the ...
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### Can an electromagnetic field be weighed?

I was going to conduct this experiment myself, but I decided to ask it. Picture a balance scale. On each pan sits a spool of insulated wire. The spools are identical. One spool is connected to an ...
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### Calculate weight needed to balance a beam

I have found many sources to determine the weight or force needed for a balance moment, but not one that included the weight of the beam as a variable. I assume this is a very simple equation. Please ...
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### How can a beam balance measure mass?

In Newtonian physics, mass is the amount of matter in an object. So, how can a beam balance measure the amount of matter in an object (which is the mass of the object).
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### Will helium in the tires of a bike make it lighter?

I know that helium balloons float because it is less dense than air. I'm not expecting my bike to float, although that would be pretty cool. I just wanna know if replacing normal air with helium in ...
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### Relatedness of weight, normal, and centripetal force

I'm taking a physics course. Since the beginning of the semester I've been troubled by this question: How do you determine how weight, normal and centripetal forces are related? I've seen plenty of ...
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### Why aren't we more heavier at midnight than at noon on the earth's surface? [duplicate]

At noon the sun and the earth pull the objects on the earth's surface in opposite directions. At midnight, the sun and the earth pull these objects in same direction. Is the weight of an object, as ...
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### Is weight a scalar or a vector?

My professor insists that weight is a scalar. I sent him an email explaining why it's a vector, I even sent him a source from NASA clearly labeling weight as a vector. Every other source also ...
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### How to calculate the maximal weight that a cable can support? [closed]

Exercise: Exercise from Theory and Problems of Physics for Engineering and Science. In the crane here the boom is $3.2 \text{m}$ long and weighs $1200 \text{N}$. The cable can support a tension of ...
Thought experiment: I acquired two boxes of the same dimensions and same weight. One box contains $1\ \mathrm{kg}$ of water at room temperature while the other box has $1\ \mathrm{kg}$ of water, but ...