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Questions tagged [weight]

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

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Would a gas “weigh” less than a liquid if they have the same mass?

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 ...
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3answers
797 views

Weightlessness under freefall

What is 'weightlessness due to freefall '? I asked this question to my teacher and he said that weightlessness experienced by a falling body when the acceleration of the body is equal to the ...
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0answers
74 views

Why does a digital body weight scale give you the wrong result when put on a soft carpet?

Why does a digital body weight scale give you the wrong result when put on a soft carpet? In particular, it gives you a smaller number. My reasoning is that if the carpet compressed "fully" (which I ...
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2answers
94 views

How to determine the weight of an object in other planets?

I was curious about what my weight would be in different planets so I found myself on this site: https://www.exploratorium.edu/ronh/weight/ But while Neptune is about 17 times more massive than ...
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1answer
782 views

Why does the scale reading depend on the position of the object on the scale and how to equalize that?

I have a KERN DS 100K0.5 industrial platform scale, range up to 100 kg, resolution 0.5 g, more or less like this: The specifications say reproducibility 0.5 g, linearity 1.5 g. When I stand on the ...
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2answers
33 views

Finding pressure of an object whose weight is known is standing on a tilted surface

In the following picture, the striped square represents a box that is standing on a surface that is aligned at $\alpha$ degree angle. Box stands on top of point $T$ (that I forgot to mark on paper), $\...
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1answer
63 views

How to get rid of electric attraction between PP (polypropylene, polystyrene) and human body?

I am doing some paint mixings involving quite precise proportions of paints. I am mixing my components in PP or PS (polypropylene, polystyrene) 60ml bottles, see: Bottles datasheet Quite often, my ...
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12answers
42k views

Why don't we use weights to store energy?

One of the main reasons why we haven't switched to clean energy is the lack of efficient storage methods - But, why aren't we using dead weights to store energy and draw it back later when needed? As ...
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8answers
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Can a ship float in a (big) bathtub?

I am confused. Some sources say it is possible at least theoretically ( http://www.wiskit.com/marilyn/battleship.jpeg ) and some say it is not true ( http://blog.knowinghumans.net/2012/09/a-...
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3answers
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Behind the scenes, when an elephant treads on a mouse

What exactly is the thing that causes the mouse to suffer more when an elephant treads on it, despite the fact that they both are exerting an equal force on each other? A quantitative description ...
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2answers
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Apparent weight in circular motion

Here's a diagram below. From my understanding, the apparent weight is the weight that you feel > which is the upward force on you > which is the normal force. I can clearly see how you'd weigh more ...
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4answers
590 views

How does a small object move with constant velocity when drag force is equal to its weight?

When drag force ($bV$) equals to object's weight (mg) then upward and downward force becomes equal. As a result the object comes to rest. If this is true, how is a body moving with constant velocity?
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2answers
169 views

Will some precious metal say gold will weigh different when moved to a different location on earth?

The weight of an object is the force exerted on it due to earths gravity, which by second law of motion is given by: $$W = mg$$ where $W$ is weight of the object, $m$ mass of the object and $g$ ...
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1answer
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What is the modulus of Tension Force in the simple pendulum experiment?

The forces acting on the bob are Tension of the string and Force of Gravity, which can be decomposed into two components: Normal or Radial one, which is antiparallel to Tension (mgcosθ) and the ...
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2answers
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Does the velocity you travel affect your weight in an elevator?

I know that if you are accelerating upward in an elevator, you will have more weight (if you are on a scale) due to normal force of the elevator pressing up into you? Would that happen if you are ...
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3answers
5k views

Does the order of the weight plates on the bar - matter?

Normally when people going to the gym and want to make "bench press" exercise using a bar with weight plates, the order of the plates (on both sides of the bar) is from the heaviest (internal) to the ...
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1answer
115 views

Does our weight depend on the floor on which the weighing machine is placed?

Any weighing machine records our weight by calculating the normal reaction that it applies on our body. So when we place the weighing machine on a smooth bedsheet, we must read a weight whose ...
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2answers
475 views

Why don't ships capsize if their centre of gravity is above their centre of buoyancy?

So our teacher recently showed us this diagram of the forces acting on a ship: However, if you tilted the ship a little so that the centre of gravity were slightly offset, surely there would be an ...
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2answers
228 views

Mass and weight

Physical quantity of mass is kilo gram and weight is Newton but generally we say my weight is some x kg why so why does this confusion if I was not wrong weight=mass*acceleration due to gravitation ...
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2answers
73 views

Does a field weighs something?

Imagine you put a magnet on a scale and you could manage to keep another magnet with the same pole above it. So the upper magnet is floating above the other one with a magnetic field in between. Does ...
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1answer
50 views

Absolute uncertainity in weight [closed]

An object has a mass of 88.60 kg ± 0.09 kg. I calculated the weight to be 869 N but now I need to calculate the absolute uncertainty in weight. My thinking was that the absolute uncertainty would be ...
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6answers
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Why do gases have weight?

I know that a gas is made of atoms or molecules moving freely in space. When these particles hit the walls of where they're kept in they cause something called pressure. But these particles never ...
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1answer
111 views

Does a solid suspended in beaker filled with Air increase the weight of the beaker? [duplicate]

When a solid object is suspended in a beaker filled with water placed on a weighing machine, the reading increases and but the object is suspended in a beaker filled with air, the reading does not ...
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2answers
5k views

Which force does a weighing scale measure?

I have come across several answers on the internet, which address the question "Does a weighing scale measure mass or weight?" but I assure you that this is not one such question. My doubt is this; ...
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1answer
415 views

What balances the weight of a horizontally rotating object?

When an object is made to rotate in a horizontal circle: Why does the angle between the plane of rotation and the horizontal decrease if the speed of rotation increases? What force balances the ...
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2answers
2k views

What is weight/mass of cumulus cloud?

This site mentions that ...the average cumulus cloud weighs 1.1 million pounds. (Scroll down the page to the cloud picture.) How, exactly, is the weight of a cloud determined? I thought that ...
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9answers
4k views

How can there be weight without movement? [duplicate]

Weight is a force. Force is mass × acceleration. When I'm standing motionless on the scale, how do I have a weight greater than $0~\mathrm{N}$ when my mass is $90~\mathrm{kg}$ and my acceleration is ...
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1answer
122 views

Calculus of Weight and mass

I am confusing about some data for calculus. First, the equivalence of weight: 1kgf=9.8N Second, the mass of 1 Newton is: 1N/(9.8m/s$^2$). And finally, to get the mass of 1kgf, I have to divide by ...
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8answers
20k views

Will a bathtub full of water weigh more if I add something that floats in the water?

Let's say I have a bucket or something bigger, like a bathtub full of water. I weigh that bath and get some value, $x$. Then I add a small boat made of wood to that bathtub that doesn't touch the ...
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1answer
433 views

What is the mechanism of a jackscrew? [duplicate]

According to Wikipedia: In the form of a screw jack it is commonly used to lift moderately heavy weights, such as vehicles. More commonly it is used as an adjustable support for heavy loads, ...
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3answers
649 views

Weight loss of a flashlight due to light emission

I watched this video. At one point, the man explains how a flashlight loses some mass due to light emission when turned on. OK, I get that. Then he talks about a different situation, where the ...
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1answer
50 views

DPD weight function

I was wondering about the connection between the weight function of the random force and the conservative force between DPD particles in a standard DPD simulation. Both usually have the form [Groot ...
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2answers
452 views

Does a scale weigh a bee flying inside a box?

This question is very similar to this one or even this one except some minor differences. The box is much larger than the bee. The box has no top cover. The bee is flying still in the middle of the ...
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2answers
90 views

Could vacuum chambers lighten the load for space bound technology?

Would cavities of near vacuums in the head (or in the 6 x 6 blocks surrounding the rocket [for reentry temperatures]) of a rocket make it lighter so it can be sent out easier?
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4answers
667 views

Fluid mechanics paradox: The force needed to 'balance' a fluid using a piston

We know that the pressure in a fluid (like water) is dependent on the depth. Consider this example: For the first setup, solving the pressure at the bottom yields $P_1 = \rho gh = 1000kg/m^3 \bullet ...
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2answers
231 views

Pressure due to weight of the fluid in fluid dynamics

In Bernoulli equation, the only term which corresponds to what one usually calls "pressure" is $p$, the other are still pressures dimensionally but their meaning is linked to kinetic and potential ...
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1answer
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Does a degassed magnet weigh less than one that is not?

I learned matter with an electric current weighs more than matter with no current. Does that apply to magnetic material in the same way but with it's magnetic fields instead of electric current? A ...
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0answers
109 views

Centre of gravity of system [closed]

We have a uniform rectangular tray of dimensions 40x60, with weight 3. We place the coordinate axes in such a way that the bottom-left corner of tray is at the origin and the tray sides are parallel ...
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1answer
12k views

Why is 1 kg of cotton heavier than 1 kg of stone? [closed]

I've been told that 1 kg of cotton has more density since Density = mass / volume, and volume of 1 kg of cotton is pretty big outside , and height of it very long, and stone is lighter because its ...
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2answers
130 views

Quick question on weight/mass [duplicate]

(In the US, just to clarify)So, from a physics perspective weight and mass are different, but when people are talking about weight in everyday(non-physics) situations ("how much do you weigh" etc.), ...
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1answer
7k views

What is difference between 9.8 N (Kgwt) and 9.8 m/s^2 (g)?

What is difference between 9.8 N (Kgwt) and 9.8 m/s^2 (g)? What is difference between kg weight and gravity? I am not so good in physics so please explain in a lot of detail (but sorry for this silly ...
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4answers
3k views

How do astronauts measure weight/mass on other planets? [closed]

At the start of The Martian movie the astronauts collect samples, targeting for "100 grams". Hence the question ... what units do astronauts actually use? I did some quick google search but all I get ...
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3answers
169 views

Need to understand concept of Buoyant force

I want to know that is there any influence created by shape of container when apparent weight is calculated for example in following figure apparent weight in all container will same or not.
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2answers
3k views

Does mass as a measure of inertia have a meaning in zero gravity? [duplicate]

Mass apart from the amount of material, is also a measure of the inertia of an object, ie. the resistance to change its motion. In zero gravity, does still mass count as the amount of inertia? In ...
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1answer
141 views

Why are we mentioning weight of the product in kg? Why not Newton? [closed]

I am confused using this units. Why this changes happened?
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1answer
11k views

Friction and surface area. How friction does not depend on surface area? [duplicate]

What will be minimum force required to move the objects in above pictures assuming the weight of the objects is same and material is also same. Will it different for each object or not? Thanks
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1answer
63 views

Do you say it right? [closed]

If someone asks you your WEIGHT what would you answer in SI Units. My weight is x 'kilogram' My weight is x 'Newton'. As we know that weight is a force due to local acceleration and still most ...
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2answers
112 views

Weight of mass falling through liquid

If I place a container of fluid on a scale and drop a non-buoyant mass into the fluid, will the scale read less as long as the mass is in motion downward as compared to when the mass is at rest on the ...
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2answers
306 views

What is my real weight? [duplicate]

My weighting machines notes my weight to be 65. Should I read it 65N or 65kg. PS: I only need a correct comment. This question is different, since, I know very clearly what mass and weight are. But ...
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3answers
95 views

Effect of internal force on the weight of an object

A man is holding a closed cage on the palm of his hand with a bird in it. When the bird flies with an upward acceleration inside the cage, it feels heavier. But the force due to the bird in the cage ...