Work Definition and 998 Threads

So the equation for work is W = F * s F = m * a, so W = m * a * s Transferring this to units of measurement gives us: J = kg * m * s-2 * m Or simplified: J = kg * m2 * s-2 Transferring back to units of quantity: W = m * v2 How can that be correct? Obviously Ekin = 1/2 * m * v2. Where did that...

Here is a little thought experiment related to magnetism and a perplexing question regarding its physics. Suppose we have a long cylinder of transparent plastic, and we press fit and then cement a circular magnet in one end of the cylinder with its north pole oriented into the cylinder. We also...

Hey everyone! This might be a bit of a dumb question, but I'm not familiar with much in the programming world. I know a few languages that I've learned on my own (online) or through a course in school (MATLAB). When it comes down to coding outside of MATLAB or a website, I'm not sure where to...

I already solved the first part, but according the my book, the answer isn't quite correct. This is what I did. Finally, I ended up with ##a=\frac{F(r-R\cos\alpha)}{Rm(\gamma+1)}##. But according to my book, the answer is ##a=\frac{F(\cos\alpha-\frac{r}{R})}{m(1+\gamma)}##, what am I doing...

O.K. here's the deal, a friend and I are taking a physics teaching methods course as an elective, as a part of the requirement we were asked to plan and execute (teach) a one hour lab on kinematics ( specifically ballistic movement), the Tracker program and error estimation. We decided on...

iam not sure of the direction of work , is it positive becouse pulleys change the direction of the force ? or is it negative because of the arrow that indicates the direction of acceleration ??!

I was just doing some review on my physics lecture and I stumble on the idea of what if there was an object hanging and the cord mass is also included in the weight and it's displaced upward without having velocity nor time hypothetically and the cord change mass. I tried solving it by W = fΔx...

CAN ANYBODY EXPLAIN HOW IT WORKS? I made it after following the instructions from a video in the net and actually it works. I cannot understand how it happens. In this motor there are no coils , magnetic fields, magnets, and brushes.There are only two bearings connected by a...

Considering the quantum mechanical model for an atom, what exactly happens when two atoms (say, two Ca2+ ions in a Brownian motion) collide with each other? As I know, this collision is not like a regular elastic or inelastic collision between two macroscopic objects. Is it mainly due to the...

Hi I have not been on the plane since 2006 since retirement, been doing cruising to avoid the security checks on the airport. I have to fly on vacation the first time. Obviously things have changed tremendously. Now everything is done on the phone. So far, I was told we can get the boarding...

I've been learning about cyclotrons recently and have trouble understanding how the ion source works. I have done some research and found that duoplasmatrons are some forms of ion sources but i don't think that's legit. I also found something called RF ion sources, but not sure how they work. I...

In https://arxiv.org/pdf/quant-ph/0203049.pdf, which is in the realm of Bohmian mechanics, Antony Valentini claims that by having a "non-equilibrium" particle with arbitrarily accurate "known" position, we can measure another particle's position with arbitrary precision, violating Heisenberg's...

Hi Guys, I want to determine the safe work load (SWL) capacity of a trestle in my workshop. It is a T Beam with width (W), height (h), thickness (t) and length (L). It is welded each end to two legs - what kind of support would this be considered as? Fixed or pin? Can someone walk me through...

I understand Faraday's law and about induced electric fields created by a changing magnetic fields, etc. But what causes the current to oscillate in an LC circuit, with no battery? If you picture that there is current going into an inductor, and that current is decreasing over time, then you...

Hello all! First post here, and I apologize in advance if this question belongs elsewhere- I'll learn as I go. I am interested in knowing more about energy and performing work. In particular, if I have an object I would like to lift, how much energy I need to expend to do that. Take for...

Relevant Equations: Specific Work Done: w = \frac{p_2 v_2 - p_1 v_1}{1-\gamma} (1) w = \frac{R}{1-\gamma} \times (T_2 - T_1) (2) Thermal efficiency: \eta _{th} = 1- \frac{1}{r_p ^ {\frac{\gamma - 1}{\gamma}}} = \frac{w_{out} - w_{in}}{q_{in}} = \frac{q_{out} - q_{in}}{q_{in}} (3) Context...

I have the definition of change in internal energy. $$ \Delta U = Q - W $$ I can get the work by $$ W = \int_{V_1}^{V_2} p dV = p \Delta V $$ however the pressure isn't constant so this won't do. ## W ## is work done by the gas and ## Q ## is amount of heat energy brought into the system. I'm...

b) Consider P_j(n) as a macrostate of the system, Bosons: P_1(1) = P_2(1) = 1/2*1/2=1/4 ,P_1(2)=P_2(2)=1/2*1/2=1/4 Fermions: P_1(1)=P_2(1)=1 (Pauli exclusion principle), P_1(2)=P_2(2)=0 Different species: P_1(1)=P_2(1) = 2*1/2*1/2=1/2 (because there are two microstates with corresponding to...

I can understand how this applies to gases as in that scenario work done = pressure * change in volume and if change in volume is zero then W=0 so change in internal energy = Q. But I do not understand how this applies generally to all types of substances, say solid, liquid and gas.

I am a undergraduate in a non clinical psychology with a special focus in evolutionary psychology, human nature, and personality. I will keep it short and sweet: - What restrictions are on me as a biological psychologist compared to that of a biologist in terms of conducting research? - Can I...

Can all the multiplexers work for any number of variables given? For example can I make a 16:1 multiplexer for 2 variables inputs, A and B?

Reactionless drives are impossible. That means that a laser carried on a satellite would produce no thrust. Why, then, would shining that laser on a light sail not produce a net force? Using a fan to blow air on a sail does not work because the fan and the sail produce opposing forces. But...

To find vx vx = dx/t = 3.86 m/1.5 s= 2.573 m/s To find Ek Ek = ½mvx²= ½(79.4)(2.573)²= 262.8 J W = FnetΔd Fnet = 262.8 J/ 3.86 m = 68 N He hits him with a force of 68N

W_net = Integral from 0 to 0.70 meters [ - F_spring - F_friction ] = 1/2 * (-k) * x^2 - mu * mg * normal force * x = 1/2 * (-325N/m) * (.70)^2 - 0.250 * 6kg * 9.81m/s^2 * 0.70 - 0 = - 89.93 Joules Is this correct and am I setting this whole thing up correctly? The negative signs have me...

The best story from space I remember is how NASA spent a huge pile of money trying to get a pen to work in so little to no gravity in space. They worked and worked away and the Soviets found the solution: using a pencil.

As I get it is that after the contact breaker breaks the contact then the current flows from plus of the battery through the primary winding then through the capacitor and to the minus of the battery. But then what happens to the secondary current? It goes from secondary coil and then what? Does...

What is the difference between the two? Also, as another question, for enthalpy, is it correct to define it to be the sum of internal energy and flow energy or is there another understanding for it? Thanks in advance

I am just looking for some opinions. I have been considering going to get my masters in Material Science (I have a B.S. in physics). I currently have a great job in the field, and it teaches me a ton. When getting my masters, I would keep the job, and they would even pay for a lot of it. I can't...

Homework Statement A charge of +3.0 μC is distributed uniformly along the circumference of a circle with a radius of 20 cm. How much external energy is required to bring a charge of 25μC from infinity to the centre of the circle? a . 5.4 J b. 3.4 J <- answer c. 4.3 J d. 2.7 J e. 6.8 J=...

Homework Statement The system is released from rest with no slack in the cable and with the spring stretched 225 mm. Determine the distance s traveled by the 3.2-kg cart before it comes to rest (a) if m approaches zero and (b) if m = 2.5 kg. Assume no mechanical interference and no friction...

I've looked at many posts related to saunas, and all have been about what happens when you pour water on the sauna rocks and so forth so I believe that question has already been answered. I've struggled to find, however, what physical mechanism governs the heating of saunas? Then, more...

Homework Statement A cart of mass M1 = 6 kg is attached to a block of mass M2 = 3 kg by a string that passes over a frictionless pulley. The system is initially at rest and the table is frictionless. After the block has fallen a distance h = 1 m: What is the work Ws done on the cart by the...

Homework Statement To lift a box it needs 250N force (F). How much work (A) has to be done to lift it at height (h) 1.2m and to slide it horizontaly (l) 1.2m. Coefficient of friction is 0.2 (μ) F = 250N h = 1.2m l = 1.2m μ = 0.2 A = ? on both situations 2. Homework Equations A = F * h A = F *...

Homework Statement Say you're launching a spacecraft of mass m from the surface of the Earth (mass Me and radius re) to a low height h (h is much smaller than r, so h is essentially negligible). How much work is required to move the spaceship from its low orbit to a great distance from earth...

I understand that downconverted light is not coherent, so that there are essentially many overlapping interference patterns and that coincidence detection filters out one of those patterns. However, could the downconverted light be filtered such that interference can be detected without...

Hi I have the educational background to do a few jobs I have seen posted as "data scientist" or "data engineer". However, I keep getting told that to get a job like that with my background, in mathematics, I need to post code examples on Github. However, I always feel like my ideas are either...

Why does a Faraday Cage work? (or more generally, why does the inside of a conducting shell have no electric field if there are charges placed outside it?) I understand that this is the result of polarisation, but why does the polarisation happen to exactly cancel out the field? Could there be...

Homework Statement A well has a diameter of 6 m and a height of 15 m.2/3 of volume of the well is filled with water.A pump can vacate 1/3 of volume of water from the well in 7 minutes 20 seconds.What is the power of the pump? Homework Equations W=mgh, P=W/t The Attempt at a Solution The...

Homework Statement Two blocks are attached to a rope across a pulley. Block A is on the ground and has a mass of 4 kg. Block B is 2 meters above the ground and has a mass of 12 kg. When the blocks are released, block B hits the floor and block A rises to 2 meters; each block has a final speed...

Did a quick search of an explosion in a vacuum and got most of what I was looking for, but on CBS Sunday morning they had a segment on restoring and reevaluating all of the immense footage of America's atmospheric nuclear testing program. They showed some amazing footage of the expansion of the...

An open tank has the shape of a right circular cone. The tank is 8 feet across the top and 6 feet high. How much work is done in emptying the tank by pumping the water over the top edge? (The weight-density of water is 62.4 pounds per cubic foot.)

Homework Statement A ball of mass m=0.300 kg is connected by a strong massless rod of length L = 0.800 m to a pivot and held in place with the rod vertical. A wind exerts constant force F to the right on the ball as shown below. The ball is released from rest. The wind makes it swing up to...

hello, I had made an DIY alpha type Stirling engine for my physics project and now I have to write an report about the relationship between the heat given to the engine and the motion of the wheel. I had searched a lot about Stirling engines and I learned about work, energy, efficiency...

Hello everyone, I am trying to build a 2-axis camera gimbal, which will control yaw and pitch. I have bought sensorless BLDC motors (GB280870KV) which I drive using SPWM. For knowing the camera orientation, I am using IMU sensors (accelerometer, gyroscope, and magnetometer) integrated on the...

Homework Statement A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope inclined at 20.0° above the horizontal. The sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is...

Following up on my previous thread, I found a project that I can do for this Arduino. Its really just a little synthesize keyboard thing, but I'm wondering how the code works. Kind of just the logic behind it. I know that some of the stuff at the bottom deals with tones and frequencies and...

When the two current carrying wires (with identical current directions) attract each other, it seems that the magnetic field of wires do work while we know that magnetic force is perpendicular to the velocity of charge. I would like to know whether the the two wires get closer or not? What about...

We are working on an IOT project in which we are trying to learn about different vibrations of using Wireless Vibration Sensor According to the manual, the wireless vibration sensor is giving the output while testing on CNC machine device 0.75, 0.71,0.69 whose SI units are in 'g'(which is...

Homework Statement A man, with a mass of 85kg, swings from a vine with a length of 11m. If this speed at the bottom of the swing is 8m/s, what is the tension if g = 10m/s^2? Given: m (mass) = 85kg r (radius) = 11m V (speed) = 8m/s g = 10m/s^2 T = ? Homework Equations Fc (centripetal force) = T...

Homework Statement Could someone look through my work? The parts where I wrote (??) are steps I am especially unsure about. Many thanks in advance. A large reservoir at temperature ##T_r## is placed in thermal contact with a small system at temperature ##T##. They end up at temperature...