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 answer is (D), but I don't understand why.
Option (A) is wrong because the work done = 0. Then, I divide the motion into 3 parts:
1) motion on snowy surface
Since the sledge is being pulled horizontally (let assume to the right), there will be tension force T to the right and friction...
1: There is a universal gravitational force between two 1 kg iron balls, and the energy generated by their mutual attraction is so small that it is difficult to observe; there is also an attractive force between a 1 kg neodymium magnet and 1 kg of iron, but the energy generated by their...
Knowing that negative work occurs when the force applied to an object opposes the direction of displacement, and that the direction of acceleration vector should align with the force vector, I assumed the correct answer was that the indication of negative work comes from negative acceleration...
Also, I wonder if a system can have work done to it due to its internal forces, as it is generally said that the work done due to internal forces is zero or at least I have learnt that(cannot trust my knowledge anymore, lol). I got this question in my mind because of a situation in another...
What I did was just sub in the numbers and convert km to m. So (6.67E-10)(1000)(5.98E24)/(1,000,000+6.37E6)^2 * (1,000,000+6.37E6) So it's just (6.67E-10)(1000)(5.98E24)/(1,000,000+6.37E6). I thought this was a straightforward problem, but it seems that it is not. What am I missing?
I've asked my question in the figure below as picture speaks 1000 words.
Code:
#include<iostream>
using namespace std;
void change(int*,int*);
int main()
{
int x,y;
cout<<"Enter values of x and y"<<endl;
cin>>x>>y;
change(&x,&y);
cout<<"In main()"<<endl...
My solution is different from the official solution and I don't understand what I did wrong.
Here is my solution:
The magnitude of the initial velocity is ##|v_0| = 12.0~\rm{m/s}##, so the vertical component of the initial velocity is ##v_{0-y} = (12.0 \sin{25^{\circ}})~\rm{m/s}##.
Then I use...
For this problem,
dose anybody please give me guidance how they got 74 K as the answer? Note that chat GPT dose not give the correct answer (it gives the temperature of the gas is 1500 K).
Many Thanks!
As part of our UG curricula in Physics major, we have a practical in which we have to draw the calibration curve of an NTC ##10~\mathrm{\Omega}## thermistor, and then construct a circuit to maintain the temperature of a water bath.
The calibration curve of our thermistor. The Prof. said that...
Based on the fact of observed cosmological redshift, scientists have proposed different ideas to explain. One interesting question is whether gravity does negative or positive work now:
According to universe expanding in Big Bang theory (Lemaitre, 1927), obviously gravity does overall negative...
I did some research online and found that "When certain elementary particles move through a magnetic field, they are deflected in a manner that suggests they have the properties of little magnets." To explain this phenomenon, physicists invented the concept of spin. So far so good.
What I...
For this derivation,
I am not sure why the bit highlighted in orange is not positive since the displacement of the piston is downwards in the same direction as the force applied.
Many thanks!
We want to figure out how much work friction does on a block as it slides down an inclined plane with a rough surface.
we find the force due to gravity that pulls the block down the ramp, that's found by M * g * sin(θ),
The normal force on the block is given by M * g * cos(θ).
The force of...
A changing current in a transformer primary produces a changing magnetic field, which induces a voltage in the secondary (correct?), but if no circuits are closed on the secondary, there's no current in the secondary (and therefore primary as well). So how is this voltage induced?
For example, if a ball is from a certain height, the work done is 0 as there is no change in total energy the Ef =Ei. However, there is a constant force applied over a certain distance, suggesting work is being done. Which aspect am I forgetting/missing? Or is it that the definition of work done...
I take the origin to be at the apex of the cone. Using the similarity of the triangle, where ##r## is radius of water and ##y## is height of water from the apex of cone:
$$\frac{r}{y}=\frac{4}{10}$$
$$r=\frac{2}{5}y$$
The mass of water = ##\rho .V## = ##\rho . \pi r^2~\Delta y## = ##\rho . \pi...
I tried to make the kinetic energy of the first electron equal to the electric potential work.
mv^2/2=ke^2/d
We have to solve for the minimum distance between them: d=2ke^2/mv^2=5.05*10^-10 m
The force is: F=ke^2/d^2=9*10^-10 N, which is not correct.
For this problem,
The answer is ##-4.70 kJ##. I am not sure what I am doing wrong.
My working is
## W = mgr\cos\theta ##
## W = mgr\cos150 ## (since angle between ##\vec g## and ##\vec r## is 150 degrees)
## W = -mgr\frac {\sqrt{3}}{2} ##
## W = -mgr\frac {\sqrt{3}}{2} ##
## W =...
I'm having trouble finding in the literature specifically about the porous silicon process using the dry method instead of the more common wet method that is used.
wet process
Using porous silicon to promote wet thermal oxidation uses the process electrochemically will allow water molecules to...
Using the adiabatic process formula, I've calculated the change in volume for a volume of gas with an initial pressure of 10 psig expanding to 0 psig. The initial volume is 100 cubic inches and the expanded volume is 144.9. This is a difference of 44.9. The total work done ends up being about...
First I found work:
W=(3.85x10^5)(2.45x10^8)
W= 9.43x10^13
Then used that for difference of kinetic energy:
9.43x10^13 = (1/2) (4.55x10^4)v2^2 - (1/2)(4.55x10^4)(1.22x10^4)^2
9.43x10^13 = (22750)v2^2 - 3.386x10^12
9.43x10^13 + 3.386x10^12 = (22750)v2^2
9.77x10^13 = 22750v2^2
9.77x10^13/22750...
I'm a little confused because my teacher used Bill's 500J of work for the kinetic energy equation and I don't understand why. I used the net work, so 300J, to find the speed and I'm not sure why that's wrong. Wouldn't friction make the wagon move slower than if there was no friction? So why...
TL;DR Summary: I want to mainly figure out where in the problem solving I went wrong. I understand the correct answer (since I looked it up), but to me, it does not make any sense.
I am honestly stumped at this point. Online solutions say that my equation y = 0.5774x-0.003354x^2 should...
Consider a merry-go-round (carousel) with a tube fixed radially on it. I use a pole to push a bowling ball slowly through the tube towards the center. (Slowly, so that the kinetic energy is negligible when the ball reaches the center. Also assume zero friction).
What happens to the work that I...
I'm unsure on where to begin with this question, i've tried many different formulas that aren't giving me the right answer. I believe to start I need to convert the kilo newtons to newtons.
I tried w = fs + mgh
w = 10500 x 8.9/sin(13.9)+(1845.69 x 9.8 x8.9) = 549986.46 J
and then convert to...
I've been getting bored of the problems I'm being assigned in math and I've been reading that Richard Feynman worked on a lot of creative math puzzles when he was in high school. I can't find a good repository of any math puzzles that require more imagination or thought than just solving...
Hi, I'm calculating the work done by regular tetrahedron during taking from the water by crane (USING INTEGRALS). I don't know how bad is that solved so if anyone checks my work and gives me some advice or hints I would be very glad.
Everything is written in the PDF file.
There were given...
I have found the work done for 100 N, 70 N and 30 N force, but I don't know how to find work for 100 N force that is acting downwards.
Force 70N:
W=F×d = 70 ×0=0 Nm (Force is perpendicular to the distance moved)
100 N force:
W=F×d=100×0.5=50 Nm
30N force:
30×-.5= -15Nm.
Please check whether...
The rotating ball should push the vehicle first to the right and once it hits the airbag - to the left?? Even if this works, how are you going to automate it and repeat it?
Promises syntax that I learnt:
let p = new Promise(function (resolve, reject) {
let x = 20, y = 20;
if (x == y) {
resolve(); }
else {
reject();
}
})p.then(function () {
console.log("that's correct");
}) .catch(function () {
console.log("that's not correct");
})
I...
One of the stages in hydrogen production after electrolysis is to run the hydrogen through a compressor and that can take a lot of energy. Would it be possible to run an electrolysis setup inside an already high pressure hydrogen tank so that the hydrogen being separated during the electrolysis...
The answer is .32m. I set the elastic potential energy as equal to the work, but at first I put the force in the work equation as (F elastic - F kinetic friction) times distance and rearranged.
1/2kx^2 = (kx-Ff) d
(0.5) (22) (0.035)^2 = (22 x 0.035-0.042) d
0.013475= 0.728 d
0.013475/0.728 = d...
I was reading a paper by J.M.C Montanus which was published in <low quality journal reference removed> in which he claims under AEST the new gravitational dynamics and electrodynamics are reformulated in close correspondence with classical physics, and subsequently leads to the correct...
photo below... Is it possible to make a machine that would take more heat from the hot reservoir to do work than what would hot reservoir give to the cold reservoir(heat)? Apparently, it's impossible because it violates 1st law of thermodynamics.
the thickness of the arrows symbolizes the...
I understand that some numbers cannot be represented in floating point but I don't understand why the way we obtain those numbers matters. In python, if I type print(0.1) or print(1/10) I get 0.1 but if I type print(0.3-0.2) I get 0.09999999... Why the difference?
What force causes the surface to move to the left?
Can I say that it's due to the force component of the weight along the vertical force of the surface?
(picture of diagram below)So the task goes like this: gas is ideal. Process 3->1 s adiabatic and in process 1->2 work done is 1200J. Fill the table.
I don't know how to calculate work done in an adiabatic process because p2 and V2 are not given and I don't know gama(Cp/Cv).
I know that deltaU...
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?
I have learned that the tub faucet lever merely blocks off the water from coming out of the...
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)?