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0answers
13 views

Weight of a material

I'm dealing with a problem here. Does a material lose weight when it transforms from solid to liquid? I believe it does. It loses weight because some of it becomes gas. Can anyone help me? Thank ...
3
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3answers
62 views

Why does the air pressure at the surface of the earth exactly equal the weight of the entire air column above it

Why does the air pressure at the surface of the earth (resulting from collisions of molecules on the surface of the earth which has to do with the velocity of the particles) exactly equal the weight ...
2
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2answers
120 views

Weight versus gravitational force [duplicate]

What is the difference between weight and gravitational force? I am a beginner who want to study physics properly.
3
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3answers
85 views

Can mass be directly measured without measuring its weight?

From Wikipedia, http://en.wikipedia.org/wiki/Mass Inertial mass measures an object's resistance to being accelerated by a force (represented by the relationship F=ma). Active gravitational ...
2
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2answers
91 views

Why do we use kilograms instead of newtons to measure weight in everyday life?

What was the reason to use kilograms to measure weight (e.g. body weight, market vegetables etc.) instead of using newtons?
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2answers
29 views

When referring to weights and mass of weights in a physics laboratory, do we use the term mass or weights?

What terminology is used to refer to weights/ mass/ weight of mass/ mass of weights when referring to the mass of weights in a physics report?
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0answers
25 views

If earth generates magnetic field does it attract metal? [duplicate]

If earth generates magnetic field does it attract metal objects at the surface of the planet and make them heavier?
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1answer
44 views

It seems wrong to find the mass using weight alone when using chemical compounds [duplicate]

The difference between mass and weight is pretty straightforward so then how can we WEIGH a substance then ask how many Daltons (atomic MASS units) are in that substance without a conversion in there ...
2
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6answers
219 views

Trouble understanding the concept of true and apparent weight

I need help understanding the concept of true weight vs apparent weight. I understand this much: if someone is standing in an elevator on a scale, the further up they go the less the reading on the ...
1
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1answer
29 views

Do different density objects in liquids affect net weight [duplicate]

I would test this but I have no tools to test it with. If I have a beaker of water and weigh it on a measure. Then I stick my fingers in the water (it doesn't over flow) does the weight change or ...
1
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0answers
44 views

Do we weigh less in the morning? [duplicate]

A question on Biology SE got me thinking, ignoring weight naturally lost during the night, "Do we weigh less in the morning?" During the night, the sun is above us, and the earth below us. ...
1
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1answer
82 views

How to weigh your nephew [closed]

My nephew is 3 and weighs around 30 pounds I am guessing. However, I would like to weigh him at home. I have kitchen scales, one flat one that goes up 1kg and one that looks like this picture that ...
1
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1answer
90 views

When you breath in a helium balloon, do you lose weight?

We all know the trick of breathing in a helium balloon to get a funny squeaky voice! When you do this, would it be correct to say you lose weight? On the one hand, the helium should make you more ...
3
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2answers
110 views

How much work will a human do to lift a weight?

I saw a pretty simple homework question here that asked how much work it takes to lift a 200 kg weight, and while the math for a basic answer is simple the weightlifter in me instead wanted to ...
0
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0answers
24 views

How does a vertical counter-weight system work?

How does a vertical counter-weight system work when you have variable weight on one side? From what I understand from this page elevators use a counter weight to counter-balance the cart and some ...
4
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3answers
528 views

Does the weight of fluid in a conical container act entirely on the base?

Scenario description Lets assume both containers have a capacity of 300 litres. One is a vertical tube as shown in pic 1 Other one is more or less a V shaped containers as shown in pic 2 Both are ...
5
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2answers
161 views

Difference between weight of water and pressure of water

(I didn't even have a basic formal education in physics. I'm learning through the internet out of my own interest, so if there are any silly mistakes, kindly bear with and guide me through.) ...
0
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1answer
44 views

Apparent weight on a hill and in a ditch [closed]

first time posting. I'm trying to solve these 2 problems. I have a solutions I just don't know if I'm right...seems odd that they are the same answer... 1) If you are driving over a hill of ...
1
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1answer
60 views

Generating forces precisely [on hold]

When we like to produce known forces, we know that standard weights acting vertically on a object creates a known force. Now, what are the other methods to generate forces with accuracy? It is a 'do ...
1
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1answer
428 views

Calculating electric motor's weight lifting ability knowing power. What else do i need to know?

So, my company works with electric motors, and my boss wanted me to calculate how much weight could be lifted by a motor rated at 750W. I know that i can't just calculate the work done by it without ...
0
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1answer
111 views

Does the weight of an magnet raise when balancing an object?

I was wondering if say I use an magnet which is facing positive and then I expel an another magnet above it which is facing the positive with its positive side and I ensure the magnet does not rotate ...
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0answers
29 views

Audio anomaly identification

I left an audio recorder in the forest in many different locations for fauna identification. I am collecting subjects on my audio recorder that are clearly not in the frequency range of any animal ...
0
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1answer
54 views

Exception to weight of hot vs cold water?

I have seen the various posts regarding the comparison of weight of heated and cold water.But is there any contradiction?I live in really hot conditions and as such tap water literally 'boils' ...
0
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1answer
56 views

Question about pendulum

I came up with this problem by myself: How much force do I need to make a pendulum revolve? Now I imagined that the force $\vec{F}$ must be enough to make the pendulum swing until half of the ...
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3answers
472 views

What limitations are there in measuring physical properties accurately?

In a StackOverflow answer, I attempted to explain why a 32-bit float was perfectly adequate for representing the questioner's weight measurement: Physical properties are inaccurately measured ...
0
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1answer
65 views

Question about resolving forces

Say, in the example below, the weight $mg$ of the object is $800N$. To find $R$, the conventional method is to use $R\sin(28^\circ) = 800$. But why isn't it possible to use instead the component of ...
1
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1answer
59 views

Estimating the weight of a vehicle moving in a highway [closed]

I need to know the estimated weight of a truck in a highway without using scales. What do I have? Speed of the car at time X RPM at time X horse power Estimated distance from a point A to B ...
1
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0answers
70 views

Perceived weight in dumbbell vs. barbell

I had an observation today at the gym when I was lifting weights. Lifting a dumbbell of 10 kg on each hand was as difficult for me as lifting a barbell with 5 kg on either end. It's true that the bar ...
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4answers
3k views

When we do pull-ups , does the bar takes more weight than when we hang down on the bar?

When I do pull-ups, I feel I push down to the bar. But does the bar really take more weight than just hang down? For people who don't know pull-ups and hang down, here is an illustration. Left: Hang ...
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2answers
155 views

Does object sealed in a airless place weigh more?

In a case where you vacuum your items in those airless bags(Space bags), do they weigh more ? Or is it just a feeling because of increase in density due to decrease in volume ?
7
votes
1answer
76 views

Why does the heaviest point on a spinning ball tend to become the topmost pole? [duplicate]

I have a mostly hollow, small clear plastic ball. Inside the ball is a weight stuck to the edge but the weight is smaller than the ball so the ball will always come to rest with the weight at the ...
1
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3answers
297 views

What makes water heavier than air?

I apologize in advance if this is too basic for this site. Considering that hydrogen is lighter then oxygen, and water is 2/3 hydrogen, and only 1/3 oxygen, and our "air" is comprised mainly of ...
0
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1answer
262 views

Effect of waters changing specific gravity on objects apparent weight placed in liquid

My goal is to monitor the change in specific gravity of a liquid over a period of time. My question is: What are the appropriate formula for determining expected apparent weight of an object immersed ...
0
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2answers
172 views

Why is this mass equation giving me mass = weight when clearly it isn't?

Convert the weight measured in pounds to the equivalent in Newtons. In the formula for determining mass based on weight, mass is measured in Newtons. Weight is measured in Kilograms, and the ...
0
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1answer
195 views

Maximum Weight Sustained by wire / Breaking limit of wire [closed]

I know that breaking stress depends on material of wire, not on the diameter or the length of wire. and also that Breaking load depends on the area of cross section of wire. But still i have a ...
0
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0answers
95 views

How do I measure the total weight of a container with scales on four corners?

I have a very large movable trash container, and I have mounted four scales, one on each corner. How do I get the total weight of the entire container? Is it simply a sum of the four weights, or is it ...
0
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3answers
77 views

How long does an object experience motionlessness at the beginning of its descent?

When a rubber ball bounces, it first accelerates in the positive direction (downward) then it bounces (hits the floor) .The velocity then becomes negative as the ball declerates while travelling ...
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3answers
3k views

Why does cold water weigh more than hot water in a fixed volume?

Take a bucket of hot water and the other bucket of cold water. Why does the bucket full of cold water weigh more than bucket full of hot water?
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3answers
582 views

how apparent weight varies due to the rotational motion of earth

I learned that as the earth rotates about its axis, the bodies on the earth also follow a circular path. In most books I read, they give the example of a person standing on a weight balance at the ...
0
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1answer
53 views

Closed cage with an helium balloon?

Does a closed cage with an helium balloon weigh the same as an empty closed cage? What if the balloon isn't touching the ceiling ? (It's a tall cage and we're weighing it in the process of the balloon ...
2
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2answers
112 views

When “weight” of an object is listed, is it really the mass or the weight?

I Have read an earlier post regarding this, but the answer wasn't perfect enough or I didn't understand so! Let me put it to clear, I know difference between weight and mass. Also I know the ...
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6answers
816 views

Does the weight of an hourglass change when sands are falling inside?

An hourglass H weighs h. When it's placed on a scale with all the sand rested in the lower portion, the scale reads weight x where x = h. Now, if you turn the hourglass upside down to let the sand ...
-2
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1answer
189 views

Change in weight by the change in mass of Earth and its radius [closed]

If the mass of Earth is four-times bigger, and the radius of Earth is two-times smaller, what would be my new weight compared to my current weight?
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2answers
140 views

Weighing a flying bird [duplicate]

Let thing of a bird standing still in a box on top of a weighing machine that shows a mass $m_0$. Now, imagine that the bird is flying, still in the same box and the same weighing machine shows a mass ...
-5
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2answers
1k views

If there is no gravity, does that mean there's no mass as well?

I have demonstrated that weight only is measured based on the gravitational pull of where you live. For example, the gravity on the surface of Mars is three times smaller than the gravity on the ...
10
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3answers
498 views

How can I weigh liquid in a sealed container?

How do you measure the mass and volume of alcohol if it is in a sealed container? Are there clever ways of achieving this? The weight of the container is not known. I can't open the container, I ...
1
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1answer
150 views

Vacuum to hold an object

How can i check and calculate if a certain vacuum pump can hold an object that weights X kg? By "hold" I mean not let that object fall to the floor due to gravity
0
votes
1answer
876 views

Relationship between angles [closed]

Question: Find the relationship between angles $\theta$ and $\phi$ using the equations of equilibrium and solve for $\theta$. Express your equation for $\theta$ in terms of $\phi$. ...
0
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2answers
402 views

What are the forces used in this weightlifting example? [closed]

You have a person doing a bench press. Their hands are equidistant apart and they are centered on the bar - each hand about 1.5 feet from center of the bar. The bar weighs 45 pounds. In example 1 ...
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1answer
81 views

Making a superadjustable barbell

My working knowledge of physics is the level of a 7th grader (if I'm lucky) so please excuse this probably totally stupid question, but my curiosity is greater than my shame: Would it be possible to ...