Help With Work Conceptualization - College Physics 1 Student

[amk0713]

Hi there. College Physics 1 student here, having a bit of trouble conceptualizing work, and would really appreciate a bit of help.

It makes sense to me that work is simply the product of force and distance. However, when force is applied at an angle, why do we only take into consideration the direction of displacement?

For example, if I am pulling a suitcase a distance of d in the positive x direction with a handle at angle theta the equation for work is W = Fdcos(theta). What happened to the y component of F? Furthermore, in this case does pulling an object at an angle decrease the amount of energy needed since displacing an object in the x direction with force applied at 90 degrees equals 0?

Thank you.

 

[antsknee]

If you try to shove your case into the Earth (y axis), how is that contributing to travel in the x axis? It isn't, it is creating more work for you.

 

[amk0713]

So in that sense, work is simply the transfer of energy into the object in question? The energy used by my arms in pulling (or pushing) in the y component is separate and dependent on a different system?

 

[antsknee]

Yes, you should concentrate on the energy placed into the object, whether F, the force, comes from your arms or an auto or anything else is not important. Force is a vector so it has components in this case in the x and y direction, you are looking only for work done pusing the case along the ground, if you wish to 'waste' some energy pushing it into the Earth that isn't what you are looking for.

 

[amk0713]

Great. Thank you. :)