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3
votes
4answers
500 views

What truly is mass, and is there a direct way to measure it?

We know a mass of an object of one kilogram as an object that weighs W = mg = 9.8 N and we reference it to that, (when it should as a fundamental parameter describe weight not the opposite). But if we ...
-5
votes
1answer
34 views

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

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 ...
0
votes
2answers
40 views

Atmospheric pressure

What is the significance of atmospheric pressure being referenced as 100 kPa ? Does that really mean 10000 kg/m$^2$ acting upon us ? If we are measuring only collision force on the surface and not ...
4
votes
2answers
23k views

Does a scale measure weight or mass? [closed]

What does a measuring scale measure: mass or weight? I mean, when we stand on a weighing scale the reading we get is in $\mathrm{kg}$'s. What does this mean?
1
vote
2answers
40 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.), ...
-2
votes
0answers
14 views

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

What is difference between 9.8 N (Kgwt) and 9.8 m/s^2 (g). What is difference between kg weight and gravity???
-1
votes
1answer
47 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 ...
5
votes
4answers
2k 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 ...
0
votes
3answers
30 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.
-2
votes
2answers
43 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 ...
0
votes
0answers
23 views

Weight or Mass? [duplicate]

I would like to ask about what bathroom scales indicate. I already read some forums about it but it just lead me into confusion. I know that it measures weight, but if it points to 70 does it mean ...
2
votes
2answers
3k views

Is there a difference between Weight and Force of Gravity?

Is there a difference between Weight and Force of Gravity or they just mean the same thing? My textbook does not clarifies this point.
1
vote
5answers
146 views

Reduced-gravity flight (A300 0-G): what is actually reduced?

I doubt I can hide from the effects of gravity when I'm close to Earth. We usually don't question this biker is fully experimenting gravity: Source. But with the well-known "reduced gravity" ...
0
votes
1answer
48 views
-1
votes
1answer
49 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
1
vote
5answers
4k 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 ...
-1
votes
1answer
59 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 ...
1
vote
2answers
45 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 ...
-1
votes
2answers
122 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 ...
3
votes
1answer
78 views

Do we feel 0.4% less body weight on mount everest?

Weight of the object at surface of earth(where $g=9.8066$). considering Weight=$100~\rm kg$ ,Weight ($W_1$)=$mg$ , mass=$10.1972~\rm kg$ At mount Everest top: Height of Mount Everest = $8.848\rm ...
0
votes
3answers
40 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 ...
1
vote
4answers
19k 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?
23
votes
17answers
9k views

Doesn't a box holding a vacuum weigh the same as a box full of air?

This was recently brought up, and I haven't been able to conclude a solid answer. Let's say we have two identical boxes (A and ...
1
vote
1answer
39 views

Who can explain me better 'the condition with no weight'? [closed]

This is related to gravity and vaccuum, which says that when the body is in vaccuum, its weight is lost. I need any examples.
1
vote
0answers
34 views

How forces divide in pulley series? [closed]

I'm trying to solve a question , It's about a lat pull fitness equipment. Here you can see what's the equipment : When someone start pulling down, How do forces divide between two pulleys ? I mean ...
-5
votes
6answers
4k views

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

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 ...
1
vote
0answers
75 views

Electric skateboard speed calculations [closed]

I have a slight issue figuring out how the mass of person (≈110kg) will affect the theoretical top speed achieved. Below are the details: (1) Motor kv : 270 kV (2) Batteries: 19.8V Motor Speed: ...
0
votes
0answers
35 views

Force exerted by pulley on ceiling

I read in my book that when a pulley is accelerating it exerts more force on the ceiling than when it is still. I know the derivation and I can mathematically prove it but I'm unable to get my head ...
0
votes
1answer
26 views

How would you solve for this system while it's accelerating? [closed]

So I'm trying to solve for this system with two weights: m1 and m2, with m2 hanging off of m1, which is hanging by two ropes off a ceiling (connected to top of m1) one rope(t1) angled 50 degrees and ...
2
votes
1answer
120 views

Confused by gravity and weight [closed]

I know that $F = mg$ so $2,00 \textrm{ KG m} \cdot 9,81 \textrm{ N g} = 19,62 \textrm{ N F}$ Why does my book say that the weight of a $2,00 \textrm{ KG}$ object is $19,62\textrm{ N}$, the mass is ...
5
votes
1answer
16k 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 ...
1
vote
2answers
46 views

Does air resistance give a falling skydiver weight?

An observer in free fall is weightless as he is accelerating at 9.8 m/s^2. However, when a skydiver jumps from a high plane, his acceleration gradually slows until becoming 0 m/s^2 at terminal ...
1
vote
2answers
109 views

What's the right way to calculate power consumption over a month given a rate per minute?

When I was searching for power required to lift an object, i found that, for example: $100\ \mathrm{kg}$ to be lifted 3 metres in 5 seconds. (vertical) Answer: $$\begin{align} ...
0
votes
0answers
16 views

Weight difference on full moon and no moon day [duplicate]

Since Moon has an impact of gravity, would same piece of mass be heavier on a no moon day (since moon is at opposite side, thus pulling downwards) and lighter on full moon day (since the moon is at ...
2
votes
2answers
44 views

Exertion of force due to spin of Earth

If Earth were to spin at a different speed would I be experiencing a different weight?
-2
votes
2answers
76 views

Could one extra straw literally break a camel's back? [closed]

I thought this was better suited here than biology, as the camel is figurative; it could also be a wooden beam. My question is basically: Could adding an object of negligible weight (such as a straw) ...
0
votes
4answers
59 views

Why consider only $x$ component of accelerating block pulled by cord at an angle?

A $5 \, \text{kg}$ block is pulled along a horizontal frictionless floor by a cord that exerts a force $F=12 \, \text{N}$ at an angle $\theta = 25 \, \text{deg}$ above horizontal. What is ...
1
vote
1answer
344 views

Force between two contacting masses on a frictionless surface pushed from left or right [closed]

The figure shows two boxes, with $m_1 > m_x$ that are on a level frictionless surface. We can apply a horizontal force $F$ either toward right on $m_1$ or toward left on $m_2$. The magnitude of the ...
1
vote
4answers
5k views

If something weighs 25 kg, how do I find the mass of the object?

An object is falling and it weighs 25 kg (on a scale, presumably). What is its mass? I know that weight is measured in Newtons and mass in kilograms, but what if a problem states that something ...
0
votes
0answers
33 views

If the weight limit of 1 wheel is 125 lbs and can 4 of those wheels together handle higher than 125lbs sitting on the skateboard?

Say I buy a wheel that has a 125lbs max load. If I buy 4 of said wheels and put it on a skateboard/longboard, does my weight get distributed such that the max weight for all 4 wheels is higher than ...
0
votes
3answers
188 views

Should these be called “weights” or “masses”? [closed]

Yeah, those circular metal disks. Weights or masses? I call them weights because when I attach them to a spring I'm interested in their weight, but it feels odd saying a "Pick up the 100g weight". ...
4
votes
3answers
18k 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?
4
votes
1answer
188 views

Why is the apparent weight smaller when you crouch down on a scale?

I am having a problem understanding the concept of the apparent weight change when you crouch down, stand up, and jump on the scale. What is happening that makes the scale change?
2
votes
1answer
63 views

Applying downward force on someone without adding to their weight

I am creating a scenario for a superhero comic, and need help with an idea. I'd like the solution to be based in scientific theory, or at least scientific fantasy, as opposed to resorting to simply ...
0
votes
0answers
21 views

Flamant's use of mass and weight

I apologize for the stupid question, but I've consulted teachers and found their answers unsatisfactory. Professor E.Brune, in the XIX century, delivered a course on l'École des beaux-arts on ...
-2
votes
1answer
229 views

Difference between mass and weight [duplicate]

I already know that when I standing on weighing machine it's measuring my mass not my weight, but when I take the same machine to moon it's will read different value. According to my information that ...
1
vote
2answers
105 views

Why is sometimes more difficult to lift a baby?

I have a small cousin and she enjoys when I pick her up, which I can do pretty easily. Sometimes though she decides she wants to make my life difficult, and when she decides so, she tells me she is ...
0
votes
2answers
43 views

Weight added to truck [closed]

If weight is added to the back of a dump truck does the height of the truck decrease in direct proportion to the weight added - does weight added equal height decrease?
2
votes
3answers
243 views

Would a person gain or lose weight after expelling a flatus?

Considering the chemical composition, mass, and pressure range of typical human flatulence, would a person gain or lose weight after passing gas?
4
votes
2answers
1k 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 ...