In science and engineering, the weight of an object is the force acting on the object due to gravity.Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar quantity, the magnitude of the gravitational force. Yet others define it as the magnitude of the reaction force exerted on a body by mechanisms that counteract the effects of gravity: the weight is the quantity that is measured by, for example, a spring scale. Thus, in a state of free fall, the weight would be zero. In this sense of weight, terrestrial objects can be weightless: ignoring air resistance, the famous apple falling from the tree, on its way to meet the ground near Isaac Newton, would be weightless.
The unit of measurement for weight is that of force, which in the International System of Units (SI) is the newton. For example, an object with a mass of one kilogram has a weight of about 9.8 newtons on the surface of the Earth, and about one-sixth as much on the Moon. Although weight and mass are scientifically distinct quantities, the terms are often confused with each other in everyday use (i.e. comparing and converting force weight in pounds to mass in kilograms and vice versa).Further complications in elucidating the various concepts of weight have to do with the theory of relativity according to which gravity is modeled as a consequence of the curvature of spacetime. In the teaching community, a considerable debate has existed for over half a century on how to define weight for their students. The current situation is that a multiple set of concepts co-exist and find use in their various contexts.
A relatively simple question has been bothering me for some time: Why is the weight of an object (the force the object exerts on a surface/rope) equal to the force of gravity that the body experiences in Earth’s gravitational field?
Earth’s gravitational field accelerates all bodies in its...
The Cavendish balance measures the gravitational constant G. To do so requires us to know the magnitude of the smaller and larger masses in the apparatus. However, mass is derived from the weight of an object, which is the gravitational force upon an object, which in turn requires the value of...
I am not sure here, even though it is probably simple. If you just hang on the bar and don't move up, you act on the bar with a force equal to your weight. But when you want to do a pull-up, I would intuitively say that you act on the bar with a higher force.
But when I think about it I would...
Hello. I want to ask for advice. I know I probably won't understand it anyway, but maybe some information will help me. I did not find a solution to this problem on the Internet, which in itself I do not understand. We moved the cabinet and I can't calculate how much the weight on the opposite...
SPOILERS
This obviously wouldn't happen to that extent, not without tearing the planet to pieces as well.
But might they feel a reduction in weight at all? Obviously it's a pretty hypothetical question without any specifics about the distances to the suns but in theory at least.
A kid is standing on a scale and holding a rope that goes through a pulley, on the other side the rope is connected to a spring and then to a 50N mass item.
Assume that the kid's weight is 700N
1. While in static mode - what will the scale show?
2. The kid is now pulling the rope to get the mass...
Hello !
According to what I have read on the internet, the weight of a body varies with temperature, its mass remaining unchanged according to the theory of relativity.
My question is what experiment is done to corroborate that the weight of a body increases with the increase in its...
I'm trying to figure out how many extra kcal I would burn on a 600km hike with a 30,000m (30km) positive gain for every additional 100g (or 1kg, whatever) of gear in my backpack.
It would obviously be a quite rough approximation, as there are significant variables such as the efficiency of a...
Not a homework assignment. Just what must be a solved problem that I'm embarrassed I don't know how look up or figure out on my own.
I want to know the total weight of a collection of N items. They are all similar but of different, unknown weights. My scale has a known accuracy of ±U units. If...
Good morning,
I'm working through the problem from the homework statement above and answered it correctly, but I can't help but feel that something important is missing.
I was able to correctly identify the sum of torques by using the following diagram, where the CCW rotational direction...
I'm not really asking for a solution for this problem I just want to clear up a confusion I have.
Why are they multiplying the weight by the sin and cosine of the 30-degree angle?
Isn't weight not affected by anything since it's constant?
Also is the angle of friction 0 because it's a...
weight pointing down
Fn pointing down and to the left (to the center of the dome)
Fs pointing ..?? Should it not be off the page? Maybe up and off the page to oppose movement + gravity?
Hi, I am trying to understand how camera jibs work.
They seem to be able to remain at whatever angle despite being balanced. The counter weight is static and does not move, yet the jib does not remain level nor does lift or drops. I have spoken to the operators and they mention they don't use...
Where
##:## really means normal ordered, in the sense that ##:A(w)B(z): = \lim_{w \to z} \left ( A(w)B(z) - \langle A(w)B(z) \rangle \right )##
##\partial X(z) = \frac{\partial X(z)}{\partial z}##
How do we go form the first line to the second one?? I am not understanding it!
it seems to me...
TL;DR Summary: Used M1V1=M2V2 but am unsure if formula applies
I feel like I could use M1V1=M2V2 but the 18% by weight ammonium hydroxide is confusing me so much.
Density of ammonium hydroxide 18% is 0.926 g/cm3
18%V1=16mg/L*200L
(18mg ammonium/100 mg of total solution) * V1 = 3,200mg...
What is and how is the estimation of the ideal weight or force to push (bit being in) a driller down when drilling (stainless) steel to bore 3-9 mm hole?
I have a VERTICAL standing square tube 1.25" x 1.25" x 1/16" thick.
Length/Height = 79"
Material = steel
How do you determine its max load capacity for this tube when mounted vertically?
I plan to use 18 of these vertical posts, evenly spaced, creating an 83" x 131" rectangular structure.
They...
I have solved the question in the following way:
The downward force is equal to the upward force. the upward force is equal to the weight of water displaced. If we find the weight of the water displaced then we will know the upward force. And since upward force is equal to downward force, we...
So i found this on a journal, and im wondering what is n and how can i calculate the weight percentage ratio between the PEO and LiClO4. Here is the instruction.
To prepare PEO-LiClO4-Al2O3 PE samples, predetermined amounts of LiClO4 (such that oxygen to lithium ion ratio is n:1) and Al2O3 (as...
This is usual induced drag diagram.
I have 2 questions:
From Kutta–Joukowski theorem Fr is always perpendicular to effective airflow.
1. Does it mean for case without effective airflow(zero induced downward velocity), Fr is perpendicular to freestream airflow,so drag is zero?
When effective...
I am a bit overwhelmed with your forum site. I was not sure where to post my question...Here goes-
Full details…I have an e-bike. It weighs about 55 pounds. I have ridden it for the last year with a canvas bag attached to the rear flat book carrier. The canvas bag measures 19” long, 9” tall and...
It's a homework question, but I feel like it fits better in this forum. The solution fails to convince me because C_D and C_L can be both written in terms of weight:
$$C_L=\frac{2W}{\rho v^2 S}$$
$$C_D=C_{D0}+k_1 C_L(W)+K_2 C_L(W)^2$$
Question:
Solution:
Any insight will be appreciated.
When car drive uphill, gravity/weight has drag component, that is reason why you must add more throttle compare to ligther car at same constant speed uphill. So logicaly car increase fuel consumption.
But if you drive downhill, gravity/weight has thrust component, so your top speed("terminal...
Hello All,
I know there are rules of thumb and thread engagement calculators online but I am trying to find mathematically what the minimum number of threads acceptable would be.
I currently have an eyebolt that will be torqued to a specific value. This eyebolt setup will then need to lift a...
Hello
The formula Mgh is commonly accepted as the work done by raising a mass by a distance h, where M is defined as the mass of the object raised.
However, is this really the mass, or the weight, simply obtained by weighing the object? If it's the weight, then doesn't the equation...
Hello there, I have tried the problem but don't get a different of 6g's as I am supposed to. I am not sure whether I interpreted the problem in the correct way, but I would love some feedback/hints on what went wrong in my solution, thanks in advance.
Solution:
SITUATION DRAWINGS + FBDS
so...
Hello,
I’m not sure if the proper term is shock load. If a person is using a device and rope to lower themselves from a high point and they’re descending fast and then suddenly stop does that create a shock load? The device attaches to the rope and when a person squeezes the device it allows...
How much Weight (W) is required to keep a weight hanging straight down when the torque is known on a rotating shaft? Please see attached image. Assume a lever weight of zero to keep it simple.
Hi,
I want to know how to calculate the effective weight if i have an object with the weight 'X' that is mounted from the side to a wall, and what happens with the weight if i increase the distance between the wall and the object.
The reason i ask is as follows for the interested.
I have a...
Good afternoon everyone,
I have a question on Newton's 2nd Law regarding objects on a generic incline. Take for example, a car on a banked curve:
Here in the picture I've provided, you can see that the normal force has been decomposed into the x and y components via sine and cosine of the...
I was watching one of Walter Lewin's lectures, he gave an example of a scale placed at your feet in a moving platform, apparently your weight changes when the moving platform accelerates downward, my question is if my reasoning is correct. I'm wondering why your feet stay in contact with the...
Hi all. I'm designing a custom spare wheel carrier for my 4wd and currently seeking knowledge on which bearings to use, so I need to work out what force on the bearings will be when it's open (closed will be locked and fully supported!)
The example image is simplified for calculation. Close...
Each weight: 2 Kg
Hello All, I'm trying to understand an "apparent weight" problem and check my answer. Please use the picture attached.
A weightless beam is at first resting over my palm, it has one 2 kg weight on each end of it. It is suspended to the ceiling by a rubber band. I drop it and...
Tank volume is 768l plus the tank and rock to go inside
2000m x 640mm wide x 600mm high
Stand is made of 35mm square x 3mm wall thickness.
Tank width is the same as the steel frame, notice the tank is not over the end legs.
Wooden top is 50mm thick pined and glued planks...
4x top supports...
Hi,
I was wondering, what is my apparent weight in water?
For example, when I tiptoe on land, my calf muscles are pretty much lifting all my body weight.
But if I were to tiptoe with just my head out of the water, how much weight would my calves be lifting?
And as I move to shallower water, how...
Since we are dealing with an ideal rope, we have that ##T_1=T_2=T_3=F and T_2+T_3=2F=(m+m_p)g\Leftrightarrow F=\frac{m+m_p}{2}g.##
##T_4=3F+(m+m_p+M_p)g=\frac{3}{2}(m+m_p)g+(m+m_p+M_p)g=(\frac{5}{2}m+\frac{5}{2}m_p+M_p)g## and ##T_5=mg-2F.##
Is this correct? If not, I woould appreciate a brief...
https://www.feynmanlectures.caltech.edu/I_09.html
“Weight and inertia are proportional, and on the earth’s surface are often taken to be numerically equal, which causes a certain confusion to the student. On Mars, weights would be different but the amount of force needed to overcome inertia...
Can you pull down/hold more weight than your body using your muscles?
Imagine a 1 to 1. One side is suspended 190 pounds, the other is me, 175 pounds. Can i, using my muscles and standing on the ground, hold that suspended weight off the ground?
I understand if i lock out my arms and...
For practice I did the following problem:
Solving this problem mechanically was simple enough using the following force diagrams:
Then
$$F_{net_M} = T - Mg = 0$$
Due to the stationary condition
$$T = mg$$
and
$$F_{net_m} = T = ma_c$$
$$T = ma_c$$
Because centripedal acceleration is...
Hello,
I am interested in making an RC plane as illustrated. Some questions:
1. Given that the build material of the plane will be 3d printed out of PLA and I want the wingspan to be between 1.2m - 1.35m ideally. How can I calculate the minimum wingspan/wing shape/wing area to carry a payload...
I found the density of carbon and iron:
ρ_fe=7.87 g/〖cm〗^3
ρ_c=2.26 g/〖cm〗^3
Using equation 2:
atom density of iron and carbon
N_fe = 8.48e22 cm^-3
N_c = 1.13e23 cm^-3
Using equation 1:
macroscopic scatter and absorption cross sections of iron and carbon
Σ_a,fe = .217 cm^-1...
how do I calculate how much force is needed to lift a horizontal metal tube to a vertical position. The metal tube is 25 feet long, weighs 300lb and and pivots 5 foot from the bottom. I will be using a hand winch and the cable attaches at the bottom of the 5 foot end of the tube.
A man and a boy hold opposite ends of 8m long pole which is horizontal. A mass of 200 kg is tied to the pole. If the man is to support four times as much weight as the boy where along the pole must the weight be tied?
Can someone please help
The force exerted downwards on the scale by the chain when it is kept on it would be
Fg= Mg
=λLg where λ is the linear mass density
However when the chain is dropped onto the scale it exerts an additional force due to its change in momentum
The force exerted by each part of the chain would...
Hello everyone. I'm building myself a half-rack for weight lifting that included 2 overhung support beams above from which to hang a safety strap incase of a failed lift. They are made from 2x3x.125 steel tube (they're Oriented with the 3" vertically). The tube are overhung by 21". How much...