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Calculate the work done by the mover

  • Thread starter raman911
  • Start date
  • #1
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1. Homework Statement
A mover pushes a 85kg crate along the floor at a constant speed through a displacement of 3,1m[E]. The coefficient of kinetic friction between the floor and crate is 0.22.
A) Calculate Fn and Fapp.
B] Calculate the work done by the mover.


3. The Attempt at a Solution
Fg=mg
=85kg*9.8N/kg
Fg=833N
So Fn=Fg
but how can i find Fapp

B] w=183N*3.1m
w=567.3
 
Last edited:

Answers and Replies

  • #2
daniel_i_l
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The box is moving at a constant speed, what does that say about the sum of the forces on the box?
 
  • #3
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plz helpp.............
 
  • #4
arildno
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What does the word constant mean??
 
  • #5
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What does the word constant mean??
not changing
 
  • #6
daniel_i_l
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Yes, so what is the acceleration of the box? How can you use that to find the sum of all the forces?
 
  • #7
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Yes, so what is the acceleration of the box? How can you use that to find the sum of all the forces?
So a=0
Fnet=0
Fnet=Fapp+Ff
Fapp=0-180
Fapp=180
is that right?
 
Last edited:
  • #8
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[tex]Given[/tex]

[tex]m=0.2kg[/tex]
[tex]\Delta {h}_{1}=0.835m[/tex]
[tex]{v}_{1}=0m/s[/tex]

[tex]Required[/tex]

[tex]{E}_{g} and {E}_{k}[/tex]

[tex]Solution[/tex]

[tex]{E}_{g}={m}g\Delta h[/tex]
[tex]={0.2kg}*9.8N/kg*0.835m[/tex]
[tex]{E}_{g}=1.63J[/tex]


[tex]{E}_{k}=(1/2)m{v}_{1}^2[/tex]
[tex] =(1/2)0.2Kg(0m/s)^2[/tex]
[tex]{E}_{k}=0J[/tex]

[tex]{E}_{T}=1.56J[/tex]
 
Last edited:
  • #9
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no response
 
  • #10
arildno
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Where did you get the 180 from, and why did you cut out the sign in front of it?
 
  • #11
Hootenanny
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Your working seems ok, but I don't know where you got 180 from. Check your math...

Edit: Dammit, thats three times thats happened today :grumpy:
 
  • #12
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Your working seems ok, but I don't know where you got 180 from. Check your math...

Edit: Dammit, thats three times thats happened today :grumpy:
soory i mean 183
 
  • #13
arildno
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I couldn't care less if the number was 54 or square root of pi fifths.

I want you to tell us:

1. HOW did you arrive at that number??

2. WHY did you take away the sign?
 

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