Questions tagged [work]

The product of the force on an object and the displacement the object undergoes along the direction of the force.

1,654 questions
Filter by
Sorted by
Tagged with
27 views

Force Applied but No Distance Travelled

Suppose I push on a wall with a constant force of 5 N for 10 s. The wall won't move and hence no work will be done on the wall. However, pushing requires energy. How can I find out how much energy I ...
20 views

How to find the work of each force acting on a block?

A push of 200 N moves a 100 N block up at 30º inclined plane. The coefficient of kinetic friction is 0.25 and the length of the plane is 12 meters. a. Find the work done by each force that acts on ...
16 views

Virtual Work and Arbitrary unit vectors

I was recently watching a lecture on MIT OCW where they were talking about Newton's Laws for a pulley system. The professor solved a problem pretty quickly using a method called virtual work. I tried ...
52 views

Work done by spring force

Consider a spring connected to blocks on it's ends lying on smooth horizontal table. Now let the right end block be displaced $x_1$ and left end be displaced $x_2$ from the mean position such ...
24 views

On source of heat energy dissipation in a system

Suppose we have a block of mass m which was at rest on a rough floor and is now given an impulse towards a wall.It is given that the collision with wall is perfectly elastic and no energy is lost in ...
48 views

The potential at a point

According to my book, 'The potential at a point is said to be 1 volt when 1 joule of work is done in bringing 1 coulomb charge from infinity to that point.' But I wonder how it is possible. As the ...
20 views

How can i calculate the friction force in this problem? [on hold]

Question: if the engine of a 1400kg car uses 25kw to maintain an average speed of 17m/s, calculate how much friction is acting on the car. my try: p = $\frac{w}{t}$, w = ΔKE, KE = $\frac{1}{2}mv^2$...
28 views

Work done by a varying angle

I know that work done by a constant force is $W=\vec{F}\cdot \vec{x}$, and that work done by a variable force is $\int \vec{F} d\vec{x}$. However, how do you calculate work done by a varying angle?
91 views

When is work actually done?

Wikipedia says: For example, when a ball is held above the ground and then dropped, the work done on the ball as it falls is equal to the weight of the ball (a force) multiplied by the distance to ...
36 views

On work done by internal forces which is coming out to be not equal to zero

1) Let us consider a block which explodes due to some internal mechanism into two smaller fragments of equal masses.The system was initially at rest and now is having some finite kinetic energy(due to ...
17 views

Energy dissipation and work of adherence force

Assume you are pushing a heavy item. But it's not moving. So there is no work, and there should also be no dissipation of energy $P=F v=0$, since the forces don't work. But we see that it does demand ...
28 views

Difference between the work done by three masses on different situations

We have 3 particles, with mass $m_{i}$ What's the difference between: i) Putting each one in a positión $x_{i}$ one by one, and ii) Putting the three at the same time in positions $x_{i}$, in both ...
14 views

Does a static-firing rocket engine do work?

Is the "working fluid" doing any work during a static-fire of a rocket engine. Since the rocket is held stationary, there is no work being done on the rocket right? However, is the exhaust doing work ...
98 views

Does the magnetic part of the Lorentz force do work?

The magnetic part of the Lorentz force is $$\vec F_L=q\left(\vec v\times\vec B\right)$$ As this force is always perpendicular to the direction of the movement, we learned that no work is done by it. ...
38 views

Why electric potential energy at a point is the same as amount of work done to bring the charge to that point from infinity?

Let's consider a positive charge at a point in the space. Now, if we want to bring a another positive charge to a point within the electric field of the first charge, then we have to do some work ...
40 views

Does a normal reaction do work too? [duplicate]

On backflipping off a wall, the wall applies an equal and opposite force that pushes the person in the opposite direction of the applied force. Or, on simply pushing a wall, the wall pushes back. Does ...
27 views

Work done by friction in a Half-Gaussian path [duplicate]

EDIT This is not duplicate of Work done by friction in a complicated path, because here exact path type is given (Gaussian), so that full integration over path can be performed and results achieved ...
86 views

Why is work equal to force times displacement?

This is how I think of what work is.I am sure I am wrong somewhere because I shouldn't be coming to the conclusion that I am coming to.It would be helpful if you would point out where this conceptual ...
30 views

Work of a fixed wall

In this link here, What work is done by the wall when a ball hits it? The answer to the question if a wall performs work when hit by a ball was, that the wall does no work if it isn't displaced. But ...
21 views

Work done on object in space

Suppose we apply a force of 1N on an object in space,due to Newton's 1st law of motion it should go on forever,therefore it's displacement goes on increasing.Does that mean that work done is infinite,...
169 views

Work done by friction in a complicated path [closed]

A block of mass $M$ is taken from point $A$ to point $B$ in a complex path by a force $F$ which is always tangential to the path. We also have coefficient of friction as $K$. What will be the work ...
29 views

How Much Power Is Required to Hover?

Suppose I have a spaceship that weighs 1,000 kilograms. I take it to the surface of the planet with a gravitational acceleration of 10 meters per second-squared. The planet has no atmosphere and I'm ...
663 views

Is the Olympic running race fair? [closed]

I noticed that the 200-meter sprints are conducted on curved tracks. (See this video: world championship semifinals 2009) Isn't that weird? I mean, just look at the curvatures of each lane! (Source)...
15 views

Friction on the surface of a pulley

1)Is friction between the part of string in contact with the pulley and the pulley same throughout the entire surface of contact ? 2)what is the linear work done by this friction when the pulley ...
40 views

How is energy conserved in terms of “Work”

Basic equation of work is given by $F\cdot s$. When work is done, the energy is stored either in form of potential or kinetic. My question arises when we look at a case of applying $m g$ of force ...
33 views

Rotational Work done by Friction

(Okay so I have asked this in a previous post but I think this should be a separate question) Consider a cylinder performing accelerated pure rolling (Static friction is non-zero) on a sufficiently ...
47 views

Why when change in kinetic energy equals to zero the work done by two opposite forces is equal even if displacement takes place?

For example if we pull a block on an incline. Then the force of gravity i.e. $mg \sin(θ)$ will be equal to force applied so that the net work done will be zero. But if $mg \sin(θ)$ is equal to force ...
I've been trying to understand the conceptual idea and purpose of enthalpy for the past two days. From what I've learned, enthalpy is defined as: $$E = U + PV$$ This leads me to my first question. ...