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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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Weight of an object without air

Consider a weigh machine and an object. Both are inside a case. Weigh the object. Then remove all the air in the case. Weigh the object again. If the weight of the object with air is M kg. What will ...
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Why is torque sometimes reported in kg m, instead of the usual N m?

On various websites I see torque expressed as $\rm kg\: m$, but I was always thought that torque is $\rm N\:m$ or $\rm kg\: m^2/s^2$. These are clearly not the same, so why are they called the same, ...
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If I drive East, how much lighter am I than if I drive West?

I'm at the equator. Suppose I am driving at x kph, in the direction of the Earth's rotation (i.e. due East), I presume that the force my vehicle exerts on the ground is less than when I am stationary. ...
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Effect of temperature on specific weight

How much of an impact has a temperature difference when the specific weight of an object in water is measured, e.g. the weight of a mussel in seawater. Would the two scenarios yield the same specific ...
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Compression of gas within a partitioned cylinder

I have been doing some thought experiments, and would like some help in thinking about two situations: a) There is a (metallic) container on a weighing machine. This container has an upper chamber ...
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63 views

What's the difference between gravitational attraction and weight? [duplicate]

What exactly is gravitational attraction? In my textbook it was quoted " all objects both tiny and large objects are attracted to the earth. This is known as gravitational attraction, or the force due ...
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Which weighs more in atmosphere, $1\,{\rm kg}$ of steel or $1\,{\rm kg}$ of feathers?

I'm having a discussion at the moment regarding the mass of $1\,{\rm kg}$ of feathers and $1\,{\rm kg}$ of steel. The person I'm arguing with states that $1\,{\rm kg}$ of feathers will be lighter ...
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Do vibrations increase an object's mass or weight?

does a vibrating object recieve an increase of mass or weight? and if it does, at what frequency or intensity does it need to vibrate at, and what is the rate of increase? is there a formula for it? ...
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Do the weights of two liquids not add when mixed?

I was given an interesting dilemma today. A co-worker saw me adding a liquid (Diisopropyl ethylamine AKA DIPEA) to a flask filled with another liquid (Tetrahydrofuran AKA THF). I needed to weigh out ...
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5answers
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What is the function of this complicated tensioning system?

I saw this arrangement for tensioning overhead cables from my train window (schematic below). Why not just have one pulley wheel leading directly to the weights? What function do the additional ...
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1answer
69 views

How to calculate the max load a metal bar can hold?

How would one calculate the amount of weight a steel bar could hold before breaking? Apologies for the terrible diagram. So if I had a steel bar of the length 18in, and the cross-section with a ...
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3answers
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How to calculate weight of an object orbiting another object?

How do we calculate weight of an object which is orbiting another bigger object in the space? For example, comparing the pair of Sun-Earth, Earth is orbiting Sun due to the force applied by Sun on ...
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How do you explain the “weight” of helium?

If weight is measured as M * g (mass x gravity), then how does the "weight" of a massive helium filled balloon negative? Let's say you have a 63,000 m^3 helium balloon. The mass of the helium is ...
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83 views

How to calculate the weight of a TV, mounted on a different type of brackets and positioned at different swirling angles? [closed]

The problem: So basically I want to calculate the weight/pressure of TV that I want to mount on my wall so I can on my own later on find the right anchors, right fittings, and TBH I am interested in ...
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1answer
34 views

Issue in conversions from force to mass units

I have a problem converting force to mass units, in this example for 9.81kgf: To get the mass, dividing by gravity, I get 1kg ...
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1answer
59 views

Conversion between mass units

I am enrolled in a course related to physics, and converting between mass units is so tricky for me. I always treat in my work only in SI units and maybe MKS units, at level of weights, I find it easy....
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59 views

Spring balance with mass in spring

Suppose I have a spring balance kept horizontally on a table, and there is a block of mass hanging from it say from the edge of a table through a frictionless pulley. Let’s say the spring in the ...
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1answer
35 views

I couldn't figure out something about mass and weight measurement

Today when I was studying physic for my University enterance exam I have stucked in one topic. I understood the difference between mass and weight. Mass is the amount of material an object contains ...
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1answer
105 views

Is it possible to create weighing machine with water indicator [closed]

I want to create a weighing machine that works with water. After researching on Google I got this. $1$ $\text{cm}^3$ of water weights $1$ g. So, with that equation I'm planned to create this below ...
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2answers
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Weight of a container of gas and container shape [duplicate]

Consider a cube shaped container with one mole of gas inside. Acceleration due to gravity would give the difference in force between the top of the container and the bottom to be mg, with net force ...
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1answer
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3 people carry a log of wood, which one is carrying the most weight [closed]

I saw this on a youtube video. The answer is that the one in the middle is carrying 25 % more than the other two. Can someone explain this?
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1answer
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Effects of microgravity on spinal disc thickness

Image is data of spinal thickness in micro-gravity or suspension experiment. I was reading an experiment on spinal changes due to microgravity in astronauts. Researchers simulated microgravity spinal ...
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When does wet cloth weigh less than dry [closed]

What liquid should you use to wet a piece of cloth, so that weight of a wet cloth is less than weight of a dry cloth? The only idea I have is that you should wet the cloth in sunflower oil and then ...
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0answers
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Ship deadweight should be deadmass? [duplicate]

The question is about ship stability calculations. We need to solve moment = force × distance, but in stability they put mass × distance. How, and why? Deadweight is the total weight of cargo, stores, ...
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2answers
78 views

Will the weight of a man standing on a scale changes if he throws something straight up?

If a man enclosed inside a chamber and the chamber is on a weighing scale and if he throws a ball straight up in air will the weight of the whole system changes or not? If yes, then what is the weight ...
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Where does the buoyant force come from?

If I place a cube in water, the force at the top of the cube, F1 will be Ahρwg. Where, A = cross-sectional area h = height at the top ρw = density of water g = acceleration due to gravity All this ...
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2answers
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Load weight on a horizontal wireframe ladder

I'm wondering about the following scenario. A wire cable ladder is mounted horizontally and a person uses the rungs to navigate from one end to the other (imagine monkey bars). If the wire cable is ~...
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1answer
130 views

What does it mean that the weight is negative?

In a recent question on the Aviation Stack Exchange, one explained that would cause an autogyro's crash. Basically, it says that the one thing that would make the gyro crash is to unload the motor too ...
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280 views

Apparent weight can be negative?

Apparent weight can be negative ?? If yes then what conditions are required for this ? If we change the frame of reference is there any change occur in apparent weight due to these changes ?
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If F = $m*a$ and $W = m*g$, why is using $F = m*a$ to calculate weight wrong?

On a test I used $F=m*a$ to calculate the weight of an object on Earth, using $9.8$ $m/s^2$ for $a$. I got the right answer, but the question was marked as wrong because I used the wrong formula and I ...
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1answer
202 views

What is Quasi-particle weight? [closed]

Hi I just heard this phrase from my classmate yesterday, I am wondering whether someone can explain this real quick for me.
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How fast does an object's weight change?

So, the title is a bit odd, I know. But I am curious, if you placed a stick that was 1 lightyear long on a scale (Yes, we are assuming that the whole stick is experiencing the same gravity as the ...
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What is the force exerted by the tire on the stone? [closed]

A stone with mass $m$ gets stuck in the tire of a car, whose radius is $r$. The car is moving at constant speed $v$. The problem asks to determine the force $F$ exerted by the tire on the stone, ...
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1answer
114 views

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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1answer
17 views

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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1answer
393 views

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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3answers
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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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1answer
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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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3answers
115 views

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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1answer
135 views

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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1answer
3k views

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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1answer
40 views

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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1answer
34 views

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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1answer
95 views

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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1answer
32 views

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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2answers
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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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3answers
170 views

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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1answer
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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 ...