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.
How do the rods and cones in your eyes work? I looked it up but didn't find any detailed explanation, and could we make them artificially to use like cameras?
One has two same volume blocks of metal, one Aluminium and one copper pushed together. If the Aluminium is instantly heated to 100 degrees C, since it has significantly higher heat conductivity will the copper draw the heat out and at some point be hotter then the aluminium? Or will it just draw...
How does apple pen II work
what is it’s principle , is the tip of pen same as optical mouse ?
how can apple pen get charged when mangenetically on iPad Pro .
thx for the help
When it comes to explaining some phenomena, I think in terms of mechanisms whereas physics explains through mathematics. With this in mind, I'm trying to compare and contrast the differences between the candidate explanations for dark energy, as nicely summarised on the NASA website...
I spend a lot of time thinking about collision problems because for me they are both extremely interesting and often very difficult to grasp when one thinks about them beyond the basics we are taught in introductory or even intermediate university courses.
Suppose there is a perfectly elastic...
The answer key is (b) but in my opinion it should be (d) because I think about work done by friction on wheel of car when the car moves. Let say the car moves to the right, then the wheel will rotate clockwise and the direction of friction acting on the wheel by the road will be to the right and...
An interesting article about theoretical physicist Chris Isham (by Michael Duff) has been posted on the arXiv,
https://arxiv.org/abs/2112.13722
Combine this with (from "Group Theory for the Standard Model of Particle Physics and Beyond" by Ken Barnes)
Isham has written two books that I quite...
Suppose you're a point on the floor and a block mass slide pass you. The block mass said " I have friction acting on me during my motion so the mechanical power is friction x my speed". When ask the point on the floor, it said "well, I don't have motion so there is no mechanical power". Yet...
My solution in shown on the attached files. The overall reaction between Mn02 is 0.81 Volts
The overall reaction which shows the reformation of the MnO2 catalyst is .27 Volts. The first reaction is more positive which shows that the MnO2 can work as a catalyst.
I have tried to draw a simplified diagram depicting the original Michelson experiment. I am only looking at the paths from the beam splitter to the mirrors at the end of the arms and back,
Below, you can see the following: A space-time diagram with two space axes (x andy) and one time axis...
So I understand the concept of lagrange multiplier but I fail at every single execise I encounter anyways.
Because you always end up with unsolvable equations of x^3yzb3gh + 37y^38x^3 + k^5x = 0
Anways here's my stupid attempt:
Instead of doing
$$grad(f) + \lambda grad(g) = 0$$
I solve
$$...
u = (9*10^9)(1.61*10^-19)^2 * (1/[3*10^-15 ]- 1/[2*10^-10])
u = 7.68*10^-14 J
but here the question. I have been taught that W= -U so shouldn't the answer be negative??
When i look up at the solution all other sources say that the W = U and therefore the answer is in postive.
This is in reference to https://epjc.epj.org/articles/epjc/abs/2021/07/10052_2021_Article_9484/10052_2021_Article_9484.html in the European Physics Journal. In it it is stated a Casimir effect produced an energy pattern similar to what is needed for an Alcubierre warp field.. Is there substance...
Here is an image for better illustration,
I only managed to solve for (a) but I'm not sure if I did it right. As for (b) and (c), I have no idea how to do it.
My answer for (a):
=> Ki + Ui + Wext = Kf + Uf
=> 0+mgh1-LμmgCosΘ = 1/2mv^2 + mgh2
=>1/2v^2 = gh1- gh2 - LμgCosΘ
=> V = √2g(h1 - h2 -...
-i had begun by finding the normal force =147 N
-then found the force of friction=99.96 N
-found the work of friction=-799.68 J
after that I am unsure of where to go since I don't have a force applied
The following image represents the system under analysis:
Using a reference point 1 on the surface of the lower reservoir, point 2 at the discharge of the middle reservoir, and point 3 at the discharge of the upper reservoir, and assuming the pressure is equal to atmospheric pressure at all of...
Let ##S## be a set of all polynomials of degree equal to or less than ##n## (n is fixed) and ##p(0)=p(1)##.
Then, a sample element of ##S## would look like:
$$
p(t) = c_0 + c_1t +c_2t^2 + \cdots + c_nt^n
$$
Now, to satisfy ##p(0)=p(1)## we must have
$$
\sum_{i=1}^{n} c_i =0
$$
What could...
Summary:: How much grunt work do you do?
Engineers out there,
What percentage of your time would you say qualifies as grunt work?
To clarify: Grunt work basically is work where you know exactly what the solution is (the problem is already solved), but you just need to push the motions...
Here's where I got the questions:
These are from a worksheet I downloaded online: Answer Key
The answer key says that the answer to the first question is 500J and for the next question it's 433J.
It says constant speed though, so I don't understand why the answers aren't zero. I get how they...
str1="hello"
for stringElement in str1:
print("str1","=",stringElement)
Strings are arrays in python and they are represented like this.
Now I want to understand how the for loop is working here.
My dry run-:
for h in str1
print h
for e in str1
print e
and so on till...
I want to understand how the weight machines work that we use in homes and shops. I have been working on force and motion chapter and I was curious how this weight machine actually push up and how it applies force to the feet of the person being weighed? What reading is this that we see in...
My Cuisinart drip coffee maker has a light that comes on, telling you to run it through a cleaning cycle (50/50 mix water/vinegar, rinse). In our previous home, we were on a well of about 750 ppm dissolved solids (including some iron), so I had an RO unit connected after the water softener to...
This is my solution ,and I just use the definition .But I still feel unclear about the concept of non-conservative force.$$ W = F x = 30N (\frac{1}{2}\pi r ) = 56.2 J $$
$$ E_{system} = \Delta K + \Delta U = W $$
$$ (K_{f}- K(i))+(U(f)-U(i)) = W $$
$$ (\frac{1}{2} *m{V_{f}}^2...
Hello, everyone. I'm not sure if I did this problem right because there's no answer key. I got this question from a high school introductory Physics book. But it's jaded and I accidentally poured coffee on it, so I can't take a picture of the question. I copied it word for word though.
This is...
Taking v = 2m/s, u=0m/s and s = 15m, we get
##a=0.13m/s^2##
##F_g = mg = 100(9.8) = 980N##
Since there's no vertical acceleration, the normal force is equal to the weight
##N = 980N##
##f = \mu_k N = 0.05(980) = 49N##
##F_{net} = ma = 100(0.13) = 13N##
##F_{app} = F_{net}+f = 62N##
My...
So this is a sketch I made of the situation
and this is my approach
my approach is incorrect , and Idon't seem to find the mistake , maybe B*p isn't correct. Any ideas?
Hi,
reading the interesting Reversible vs Irreversible Gas Compression and Expansion Work insight by @Chestermiller I would like to ask for clarification on some points.
In the second bullet at the beginning
my understanding is as follows: consider an ideal gas contained in a cylinder...
Hi everyone!
I just bought the courant John calculus volume-1 from uni bookstore. I need some tips like errors, topics which are not explained well and topics which are really important and need to focus more on etc..
My background:- have Spivak as a supplement. Knows how to prove and read...
I feel like I've gotten stuck on this. I know the work done is equal to the kinetic energy of block A, but I can't figure out how I would find the potential energy stored in the spring without using the spring constant in the equation. W = FA * dA + U
In classical and continuum mechanics if we want to find equation of motion of the body we draw force diagram and apply Newton's 2nd law.
In continuum mechanics, equation of motion actually refers to a special point of the body known as center of mass (COM) which can be proven by definition of...
Mods, I know "General Engineering" hardly describes this question, but it doesn't seem to fit anywhere. Move it where you wish.
There's a trick that works with most tape (especially packing tape), where you fold the tape on itself, make a crease, then pull the creased tape apart quickly. The...
Work - energy principle states that work done by net force acting on the body equals change in kinetic energy of the body. We are talking about continuum mechanics. This principle is usually introduced in mechanics of solid bodies. For us to describe the motion of the body, it is enough to know...
A new result from Purdue https://www.purdue.edu/newsroom/releases/2021/Q2/the-whitest-paint-is-here-and-its-the-coolest.-literally..html
Is about the development of a new paint that is the whitest yet, reflecting 98.1% of solar radiation. That is so much that they claim that it causes a...
I tried to solve it by integrating force from 0 to L
dF=dm.g
where dm=λdx
And then I multiplied it with velocity to get power because velocity is constant
∫(vdF)=v ∫(dF)
But the book used integration to find work done and divided it by time for power
My answer was λlgv(Option B)
Giving...
Work - Energy principle states that work of resultant force or sum of work of all forces acting on some system equals change in kinetic energy of the system.
For inviscid fluid flowing in a pipe such theorem can be used to derive Bernoulli's equation because as fluid flows it is subjected to...
I really can't get my head around the concept of pulsed plasma thruster. All I know now is that it utilizes ##\vec F=q \dot {\vec r}\times \vec B##. Could someone explain the mechanism to me, please? Thanks!
1) What is the relationship between gravitons and the curvature of space-time?
2) As gravitons move at speed c, the curvature of space-time is not instantaneous either, so how the curvature sets in or disappears gradually (for theoretical example if mass disappears suddenly upon collision of...
Got a question from my science exam that I'm not sure how to figure it out. All the context I was given is attached.
My attempt:
Mass=26kg
26a = Force
Work = 26a x 2
Work = 52aNot sure how to figure it out, as 52a is the wrong answer.
I first worked out the buoyant force using rho = 1000, g = 9.8 and V = 1. (this gives Fb = 9800)
I then worked out Fg of the tank (5 x 9.8 = 49)
Then I used Fnet = Fb - Fg - T = 0 to work out tension as 9751.
I thought the work done would be the work done by tension (9751 x 50.4), but I'm not...
Let’s say we have two persons who are going to travel from Central Park in New York to the Golden Gate Bridge in San Francisco. One is going to walk and the other is going to use his skate board. And let’s say they weigh the same and take the exact same route.
the question is this...is the...