In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, it is often represented as the product of force and displacement. A force is said to do positive work if (when applied) it has a component in the direction of the displacement of the point of application. A force does negative work if it has a component opposite to the direction of the displacement at the point of application of the force.
For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). When the force F is constant and the angle between the force and the displacement s is θ, then the work done is given by:
W
=
F
s
cos
θ
{\displaystyle W=Fs\cos {\theta }}
Work is a scalar quantity, so it has only magnitude and no direction. Work transfers energy from one place to another, or one form to another. The SI unit of work is the joule (J), the same unit as for energy.
The solution said that Average power= net change in energy/time, but why is that true? If you have a different way of solving it, it would be helpful too
I need a method to accelerate a ball bearing down a pair of wire tracks, and to generate a consistent amount of force on every activation. Please critique my tentative design:
I want to use an inductive coil activated by a proximity sensor to generate a transient EM field to accelerate the ball...
So, from what I remember, W=F*D*cos (θ). If I'm lifting, θ=90° and so, the cos = 0. So is the work just 0? Why? I still moved the object through a distance, which is the usual non-mathematical definition of Work.
As we know, when we turn on a tub/shower combo the water initially starts to flow out the tub faucet. When the lever is raised, the water is diverted to the upper shower head. How does this work?
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In defining the heat capacity of a subatance as the constant relating change in temperature to change in heat, is it assumed that the system does no work? Does it really say (heat capacity is the constant relating heat change to temperature change when the system does no work)?
Hello,
Suppose I have a spherical hole in a elastic infinite space. I apply a time-dependent pressure to the inner surface of the spherical hole.
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Hi all,
I just read this article about how electrical transformers work and have some questions.
https://www.dfliq.net/blog/the-basics-of-electrical-transformers/#:~:text=The%20three%20important%20components%20of,magnetic%20flux%20is%20initially%20produced.
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In this 2D figure below, I can place:
a motor at O
a motor at J
gravity on each link
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Hi, everyone! There are a lot of work energy conservation laws and I get confused which one of them summarizes all of them. Which one I should keep with me and rest should be easy to derive on spot ?
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Hi guys, I'm about to start my degree in a few months and I know what field I want to major in but I don't know what track I should take. In the future I want to work with rockets and spacecraft engines, I want to help develop the new generation. Correct me if I'm wrong but it's called a...
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I did a prac where we tried to calculate the rydberg constant for hydrogen. We had a hydrogen lamp and we used a spectrometer that was hooked up to a photomultiplier tube to detect the wavelengths of light corresponding to the balmer series. In one section I need to write up a brief summary of...
Ubuntu 22.04.1 has been released recently, and the Software Centre shows that my system is ready to upgrade. I want to upgrade, but I am a bit afraid because there is no option to rollback the upgrade. I have a number of applications that are essential and I need them to work properly:
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Hello !
I've got a problem understanding what are Lumens and how do I look at lux as well.
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I recall that there was an argument from Born expansion showing that exchange of odd spin between equal sign charges generates a repulsive potential, and if the charges are different or the spin is even the potential is attractive.
I wonder, how does it work for non abelian gauge theory...
just hypothetical question,
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I already know the solution to this, all you do is set the height of the top of the trampoline to 0 and solve for initial velocity so the equation for the conservation of energy $$mgh_0 + \frac{1}{2}mv_0^2 + \frac{1}{2}kx_0^2 = mgh_1 + \frac{1}{2}mv_1^2 + \frac{1}{2}kx_1^2$$ becomes...
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.
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I tried using the 109 J to convert to seconds but that didn't work. I also looked through the energy equations but nothing worked. I am not sure how to find time.
Hello physics researchers, teachers and enthusiasts.
I notice one little thing is confusing me in the derivation of Bernoulli's equation in the article, they write:$$dW = dK + dU$$where dW is the work done to the fluid, dK is the change in kinetic energy of the fluid, and dU is the change in...
Hi! So, I've actually already solved this problem.. for the most part.
I have split up the work into two sections, floor 0 to 10, and floor 10 to 15.
From floor 0 to 10, I did
## F_{elevator} = w_{pass.} + w_{elev.} ##
## F = (70)(20 (num. of pass.))(9.8) + (800)(9.8) ##
## F_{elev.} = 21560N...
Hi. I'm a high school student interested in applied math, including but not limited to climate modelling, auto differentiation, and simulations. It'd be really nice if I could get some experience in those fields in a structured learning environment, like an internship, with mentors if possible...
A convergent version ( i.e. convergent in the critical strip) of the traditional series for the Riemann Zeta is derived in the video linked at the bottom. It gives the correct numerical values (at least along the critical line, where I tried it out).
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Does Ohm’s Law, V = IR work for light bulbs? It appears not to from my simple experiment below.
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I don't understand what I have done wrong in part (c) I have the initial velocity for the second part of the motion and have the final velocity zero and then the net work done is W_mg + W_Fs and the actual answer for x is 2.37m
Could I get some help/tips please, thanks in advance.
Here is my...
I'm very skeptical of supplements and other products that supposedly boost testosterone and brain health. They are always on TV, and I wonder if they are just snake oil OR if there are any ones that actually do benefit the body. My mother takes Magnesium Glycinate every night to keep her...
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During a thermodynamic cycle, an ideal thermal machine absorbs heat Q2 > 0 from a hot source and uses it to perform Work W > 0, giving a cold source a heat Q1 < 0 with an efficiency of 20% . How much is the work done as a function of Q1 ?I have 2 question regarding this problem: 1) Why is Q1 the...
This is a thermodynamics question. A gas absorbs 10 000 J of heat , it releases 3000 J and does 2000 J of work. How much has the internal energy varied?
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I'm installing 4 motorized dampers in my basement HVAC, the motor on each unit is 24V drawing 6 watts at 0.25 Amps. I will be powering them from one 24V 40VA transformer. One temperature controller, that uses direct output and has a max output capacity of 10A, will be installed between the power...
Hi there, this question has already been discussed in this forum, however I do not know how to proceed further and if my reasoning is correct.
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I am a mechanical engineer and my experience with electrical systems is almost nil.
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hi everyone, i need to build a dc motor for my school project. I have used copper wire for the turns (60 turns), wood to build the structure of the armature and commutator. i have used neodymium magnets as my permanent magnets and paper clips as the brushes. I tried using a 9v battery with a...
The equation I know for adiabatic work is W = P1V1((V1/V2)ϒ-1 - 1))/ϒ-1, but this involves ϒ, but I can use ϒ = Cp/Cv = Cv+R/Cv = 1 + Cv/R, does this seem correct? But I still have a P1
a) ##\rho = \frac{I}{c} = \frac{F}{A}## for a perfect absorber
##F = ma## where ##a = \frac{c}{t}##
##\frac{I}{c} = \frac{mc}{tA}##
##I = \frac{I^2 tA}{mc^2} = \frac{P}{A}##
##P = \frac{I^2 tA^2}{mc^2} = \frac{W}{t}##
##W = \frac{I^2 t^2A^2}{mc^2}##
I am unsure what A is. I think it should be...
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Hi guys I am doing a graphic design project and I would need to know how this tests to check if your drink is been spiked works. Whats the chemical that react to the most common drugs used?
thank you so much!
Hi PF!
I'm going through a backtracking tutorial here. That code runs well for me, and is below:
%% LOAD DATA
% Read a table of daily adjusted close prices for 2006 DJIA stocks.
T = readtable('dowPortfolio.xlsx');
% For readability, use only 15 of the 30 DJI component stocks.
assetSymbols =...
I will summarize briefly my reasoning for both letters, since the answer is immediately after that:
A) The work is quasi-static, and the pressure is approximatelly constant and equal to the atmospheric pressure, so the works is $$W = -p\int dV = -p_{0} (V_{0}-V)$$
B) The work is fast, fast...