All Questions
129 questions
1
vote
6
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"Kilogram" confusion: If you weigh a stationary object in "kilograms" and divide the result by about $9.8$, does that tell you the mass of the object?
Update: I appreciate all of the answers very much
In a way, I'm delighted to find that such a simple question has generated so much disagreement (most of which can be attributed to issues with wording,...
- 135
0
votes
2
answers
115
views
Why do objects with greater length feel heavier - and how to calculate perceived weight?
Consider this situation:
As part of some training, you are asked to pull an object that is 100 feet long, weighing approximately 218 pounds across a distance of 310 feet (fire hose across concrete if ...
- 103
0
votes
7
answers
135
views
How does $m$ fit into the equation for weight?
I know part of the answer to this question because I know the equation, $W=mg$, and I know what $g$ signifies, which is the acceleration due to gravity. This acceleration is always the same on Earth ...
- 569
1
vote
4
answers
116
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What is definition of weight?
What is definition of weight? Does weight of an object change under water, or the weight remains the same, but the: 'apparent weight' = 'weight' - 'buoyant force' ?
Same question for object submerged ...
- 121
0
votes
2
answers
49
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Mass/weight in 2 places at the same time
Though it may seem like it is not, this is a genuine question of which I cannot find the answer online. The situation of how the question arose may make it seem otherwise.
I monitor my weight every ...
0
votes
1
answer
202
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How do you measure mass? [duplicate]
I feel like I am missing something fundamental with regards to mass vs. weight.
The weight of an object on the Moon is approximately 16.5% what you would experience on Earth.
In other words, if an ...
- 171
0
votes
1
answer
37
views
How does added weight of 100kg affect the height of a originally 1m stack of paper [closed]
Lets say i had a stack of papers, 1 meter tall. Assuming that each paper would be around 0.1mm in thickness, the total number of papers should be 10000. Now, when placing a weight of 100kg on top of ...
- 103
2
votes
1
answer
644
views
Weight at an angle
My physics knowledge is pretty basic, somebody suggested that I'll get the definitive answer of below question here.
Imagine a barbell of mass m (kg) which is ...
- 23
0
votes
1
answer
63
views
Does the weight of a car increase under cornering? [closed]
Lets say we have a car with a mass of 1000kg, and lets say the car turns a corner fast and pulls around lateral 3g. Since under normal condition car weights 1000 x 9.81 (1g) = 98100 Newtons , will the ...
7
votes
4
answers
613
views
If I weigh 150 pounds on earth, does the earth weigh 150 pounds on me?
Weight is mass times gravity. My gravitational force is a very small amount compared to the earth. So if I weigh 150 pounds on earth (my mass * earth gravity), then shouldn’t the earth weigh 150 ...
- 83
-4
votes
1
answer
108
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Is it correct to take density of water as 1 g/cm3 for physics numericals? [closed]
In solving physics or physical chemistry questions, generally we take density of water as 1 gm/cm^3 or 1000 KG/m3 and according to our daily experience it is correct as often times we have experienced ...
- 493
0
votes
1
answer
617
views
Does two objects of the same mass weigh differently in moon and earth if their densities are different? [duplicate]
you have a bag of cotton and an iron bar, each indicating same mass when measured on a weighing machine kept on earth. if you weigh the two objects in moon, which (if any) will weigh higher?
1
vote
1
answer
299
views
Tension force in kilograms [closed]
Suppose I want to buy a cable that will support & pull a mass of $2\ kg$ upward at an acceleration rate of $2 m/s^2$, I must specify the maximum mass the cable will carry.
I know how to calculate ...
- 23
1
vote
2
answers
50
views
On the difference between mass and weight as it applies to formulae
How exactly does weight work in terms of various formulae include mass? For instance, for the momentum of an object, does momentum increase with greater gravity? Or is it only dependent upon mass ...
- 227
0
votes
1
answer
123
views
Is the non-technical definition of weight same as mass or is it also affected by gravity?
Technically, weight is the force which an object applies in downward direction, with Newton as its SI unit. However in non-technical usage, weight is a measure of heaviness or lightness of an object, ...
- 47
0
votes
2
answers
47
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Simple dynamics im really confused
So my question is a little dumb: if an object on a scale has a weight that points downwards and the scale exerts normal force on the object upwards, cancelling the forces acted on the object then what ...
- 5
3
votes
1
answer
528
views
If 1 gram force on Earth is 0.0098 N, what would it be on Mars or others?
I know that this is a very simple question, but I am not really sure about this. If 1 gram force on Earth is $0.001 \;\text{kg} \times 9.8 \;\text{m}\,\text{s}^{-2}$, what would it be on Mars or any ...
- 263
0
votes
2
answers
216
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Why $\rm kg$ in daily life but not $\rm kg~m/s^2$? [duplicate]
I had a question regarding weight so here I begin
W=mg (where w=weight,m=mass,g=gravitational acceleration)
w= kg*m/s^2(kg is the si unit for mass and weight , m/s^2 is the si unit of gravitation)
w= ...
1
vote
1
answer
37
views
Why do physics textbooks mention weight when saying mass? [duplicate]
I've always found in physics textbooks (and in general too) that when a paragraph or question mentions mass it actually is succeeded by weight of the object in question.
For example,
The mass of the ...
0
votes
2
answers
352
views
Do things weigh the same in different orientations?
What experiments have been done to check that objects weigh the same in different orientations?
To what accuracy has it been checked that the two weights of the same object in the positions below (for ...
- 13.8k
-1
votes
2
answers
97
views
Max angle to avoid cart crash [closed]
How can I calculate max angle to avoid my cart to roll out or crash ? I need to move a weight of 3 kg at a height of 2 m, with a cart that weights 20 kg.
Here attached an image:
I would like to find ...
- 11
0
votes
1
answer
105
views
Discuss the possibility of using force rather than mass as the basic quantity. (Kibble, Classical Mechanics)
I'm starting first year in the Autumn and I'm doing some pre-university maths and physics. One of the questions I had a go at doing was this one, from Classical Mechanics by Kibble:
Discuss the ...
3
votes
3
answers
890
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Astronauts being able to move "heavier" objects easily in space
I was watching this video where the astronauts demonstrate how an object that would weigh some large amount on Earth is nearly weightless in the microgravity experienced onboard the ISS.
What I don't ...
- 153
1
vote
4
answers
838
views
Difference between Kilogram-weight and mass
I got really confused about this $\text{kg-wt}$ and mass when I went through a question which says
A body weighs $700\text{ kg-wt}$ on Earth surface. How much will it weigh on the surface of a planet ...
- 89
2
votes
1
answer
301
views
What is Newton's original definition of mass?
What is Newton's original definition of mass.
The following is from the English translation of Newton's Principia by Andrew Motte.
"The quantity of matter is the measure of the same, arising ...
- 159
2
votes
2
answers
345
views
What does it mean that the relationship between material mass and weight is constant and proportional?
I hope someone can help me with this apparently very basic doubt, but I feel like a stupid monkey trying to join two sticks to reach bananas and without success. My English is not good, I am Mexican ...
0
votes
1
answer
983
views
Understanding what a scale outputs and converting between Mass and Weight
I understand that weight is a measure of force acting on an object due to gravity and mass is a measurement of the quantity of matter than an object contains. With mass having units of kilograms or ...
1
vote
1
answer
182
views
Measuring the correct mass or weight of an object in the presence of atmospheric pressure?
I know due to atmospheric pressure the weight of an object increases, but when we take measurements we do not omit the weight of the column of air above it. So, doesn't it affect the accuracy of our ...
- 195
2
votes
2
answers
6k
views
Bath-Scales weight or mass?
I read that bath scales measure body weight and not mass which means they measure m*g and not m.
If I got a reading of 50 kg, does that mean that my mass is nearly 5?
Units of m*g aren't kg so why ...
- 33
0
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2
answers
1k
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Does weight have any function in vacuum? [closed]
As we know, that in a vacuum, bodies with different masses fall with same acceleration, which is due to acceleration due to gravity.
But Weight of a body is dependent on mass as well.
So, is it so, ...
- 99
0
votes
2
answers
210
views
How is weight $W = 0$?
One of my physics teachers told me that in the formula of calculating weight i.e. $W = mg$, $m$ is not equal to 0 until and unless you're travelling close to the speed of light. She added, that the ...
- 31
1
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2
answers
162
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Does adding weight to a person affect the time taken for a person to run 20 metres?
I am doing a science experiment to see if adding weight to a person affects the time taken for a person to run 20 metres. I am needing to write some background information (1 page) and I am not too ...
0
votes
2
answers
58
views
If an elevator and its shaft were weighted, would they weight less as the elevator goes up?
I have a question that would probably be easy for you.
If we could put an elevator together with its shaft on a scale and have its motor pull it up, lets say for 50 floors.
will the reading on the ...
- 103
3
votes
2
answers
248
views
What saves bike rims when one rises before hitting small obstacles at full speed?
When riding a road bike with thin tires over small obstacles such as tree roots, there is a risk of damaging the tires.
Cyclists argue that rising off the saddle will all but eliminate the risk of rim ...
- 179
1
vote
2
answers
706
views
60 kg on earth is 60 kg on the moon [closed]
I'm writing a trivia quiz and intend this question, which dates from a high school physics test I took in 1972.
An astronaut tips the scale at 60 kg while on earth, what will she be if she steps on ...
- 27
0
votes
6
answers
548
views
Why do we treat weight as acting on the object?
When drawing force diagrams I am really struggling to understand why we put the weight of an object as a force acting on it, rather than as a force acting on whatever else there is around it.
For ...
- 127
0
votes
1
answer
127
views
Definition of weight
As per CGPM the official definition of weight is
"The weight of a body is the product of it's mass and acceleration due to gravity."
When I searched for gravity it defined gravity as the ...
- 153
0
votes
2
answers
4k
views
How much is my weight in Newtons? What is my Mass?
We refer to our earthly weight in "pounds" or "kilograms". The Force I put on my scale is mass × acceleration = mass × 9.8 m/s^2.
My scale reads 98 kg, yet the units of Newton are kg m/s^2. Do I ...
0
votes
3
answers
534
views
How to differentiate between mass and weight? [duplicate]
Today while solving numericals in my physics book I got struck over a question which said "A hammer weighing 1kg .....".
In the question they told that the weight of hammer is 1 Kg but when i checked ...
user223406
1
vote
4
answers
221
views
Is the notion of 'weight of Earth' meaningless? [duplicate]
I am not talking about the distinction between mass and weight, just the concept of 'weight'.
In University physics (book by Young & Freedman, 14th Ed.) it is given that
the weight of an object ...
- 1,039
1
vote
4
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4k
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Weight and Inertia (are they related?)
R. Feynman wrote in his lecture (The Feynman Lectures on Physics: Chapter-9)
"Weight and inertia are proportional, and on the earth’s surface are often taken to be numerically equal, which causes a ...
0
votes
3
answers
164
views
How do we define "mass" in the context of particle physics and relativity?
In laypersons terminology, mass is defined as the amount of matter. However, consider the following:
The $W$ and $Z$ bosons have mass.
An antiparticle has the same mass as its corresponding particle.
...
- 541
2
votes
2
answers
90
views
Weighing machine, kg vs. N
When I stand on a weighing machine and it shows me the number 75 , is it my mass in Kg or the Normal Force due to gravity in N
user232243
1
vote
1
answer
637
views
How is weight dispersed among multiple points?
I was recently viewing remembrance photos from the 1995 bombing of the Alfred P. Murrah Federal Building on MSN news where slide nine shows a photo of firemen teaming up to carry a $40'$ steel bar ...
- 140
3
votes
2
answers
878
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Ought we say 'body mass', rather than 'body weight'?
I'm asking in the context of medicine, where you're "massed" (or is it "weighted"?) on a scale.
This answer beneath insinuates that 'mass' may be the preferred term, but it doesn't outwardly clarify ...
user53143
2
votes
2
answers
142
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How do you determine weights from CG when there are more than two locations
On the internet they list ways to calculate weights based on CG when there is a weight on the left and on the right of your CG.
Most of the examples show a box truck for determining the weight on the ...
- 165
0
votes
3
answers
279
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Satellite Motion centripetal force
Once I read in a book that the centripetal force that keeps the satellite in its circular orbit around the Earth is approximately equal to its weight.
My question is why the word "approximately" was ...
- 367
-1
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2
answers
276
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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 ...
- 49
6
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4
answers
8k
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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, ...
- 63
1
vote
3
answers
1k
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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 ...
- 117