Problem in calculating work done?

  • #1
navneet9431
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Homework Statement


IMG_20180817_085052.jpg

See question number 3

Homework Equations


Work Done="integral" F*ds

The Attempt at a Solution


I tried to solve this question using integration,
IMG_20180817_085548.jpg

I have replaced F with "1" and ds with "t^2+2t".
So I am stuck in at that step.
Please help me differentiate it further or solve it further!
I will be thankful for any help!
 

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Answers and Replies

  • #2
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In the integral it’s ##F*ds## which becomes ##F*dx## so you can’t just sub in the ##t^2+2t## term.

##dx/dt = 2t+2## and so ##dx = (2t+2)dt##
 
  • #3
navneet9431
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107
9
In the integral it’s ##F*ds## which becomes ##F*dx## so you can’t just sub in the ##t^2+2t## term.

##dx/dt = 2t+2## and so ##dx = (2t+2)dt##
Thanks for the reply!
But can you please explain why is it wrong to substitute "t^2+2t" in place of ds?
 
  • #4
haruspex
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Thanks for the reply!
But can you please explain why is it wrong to substitute "t^2+2t" in place of ds?
You are not given ds (or dx)= t2+2t; you are given x=t2+2t. So what does dx equal?
 
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