(adsbygoogle = window.adsbygoogle || []).push({}); I'm just learning work in my physics class and, for some reason, I'm having difficulty understanding it. The problem in my homework assignment asks:

A particle moves 5 m in the positive x direction while being acted upon by a constant force F = <4,2,-4>.The work done on the particle by this force is:

I know that there are several useful equations which I should use when it comes to work,

W = ∫F*dr

K = 1/2mv^2

Ug = mgy

Fs = -kx

Us = 1/2kx^2

but I don't know how to apply any of these equations to this problem. I tried the first but was unsure of what F should be because F consists of i+j+k. I found the magnitude of F and plugged it into F but then didn't know what to do with the integral... so I got ride of it and just multiplied it to 5m.

I got the wrong answer so I tried with another approach. Again, I got ride of the integral because it's indefinite and I wasn't sure on how to find the constant (I am taking this integral to literally? Is it more symbolic than mathematical?) but this time I decided to make F = 4 because, in the vector <x, y, z> 4 was the x, or i, component of the equation, and I got the right answer!

So my question is, does this apply to all cases? If I was given dr and the vector force <x,y,z> does the work depend the direction the particle moves through?

For example,

F = <1,2,3>, dr = 5m.

Particle moves in the x-direction, W = 5J.

Particle moves in the y-direction, W = 10J.

Particle moves in the z-direction, W = 15J.

Thank you for taking the times to review my question.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Introduction to Work, do I have the right concept?

**Physics Forums | Science Articles, Homework Help, Discussion**