Quick question about work

  • #1
[Note by mentor: This thread does not use the homework template because it was moved here from a non-homework forum.]

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Okay i've issue related to work so i thought i should ask here. Its really frustrating I've tried everything but I just can't figure out how to find work.
Question:
A set of frictionless wheels are attached to the bottom of a box, which is then measured and found to have a mass of 6.0kg. The box is placed on the floor, and a student of Physics uses a brief horizontal force of 150N to push the box sideways, after which the box rolls across the floor with constant velocity. How much Work does the floor do on the box as it rolls along?

since work is w= fxd and there is no distance given. also that to find a distance you need time and there is no time given either. I can't figure out how to do it, any ideas please? thanks
 
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Answers and Replies

  • #2
A.T.
Science Advisor
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since work is w= fxd and there is no distance given
What is the value of f? Do you really need d in this case?
 
  • #3
f is Force and work is force x distance so yes I need it. I can't think of else way
I tried other formula too which is Work = 1/2mv^2 but velocity is constant has no value so no idea.
 
  • #4
russ_watters
Mentor
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If there is no force being applied, there is no work...so why do you need the distance it rolls without a force?
 
  • #5
150 N Force is being applied, it says in the Question
 
  • #7
By a student of physics who is pushing it horizontally
 
  • #8
russ_watters
Mentor
21,177
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By a student of physics who is pushing it horizontally
But that isn't the force that the question asks about.
 
  • #9
so you are saying that there is no work done because there is actually no force acting on it?
 
  • #10
A.T.
Science Advisor
11,454
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so you are saying that there is no work done because there is actually no force acting on it?
What does the formula for work say if f=0?
 
  • #11
If force is zero work would be zero too becase formaul is force x distance. but in question its implying that work happened as box moved
 
  • #12
A.T.
Science Advisor
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question its implying that work happened as box moved
You have to read more carefully what it says/asks. It asks about work by floor, not by the student.
 
  • #13
380
7
Frictionless means there is no friction force, right?
 
  • #14
Yup i figured that and I must admit that I was being stupid and I didn't read the last words properly that work done by "floor" which is doing nothing cuz wheels are frictionless.
ahhh not a good feeling. no.
thanks mate.
 

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