Force Vector Magnitude Distance

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SUMMARY

The discussion centers on calculating the work done by a force vector, specifically F = i + 2j - 3k, on a particle moving 10 feet in the direction of the vector i + j. The work is computed using the formula W = ||F|| dot product d, where d is the displacement vector. The initial calculations presented were incorrect due to a misunderstanding of the dot product operation involving a scalar and a vector. The correct approach requires ensuring that both vectors are appropriately defined for the dot product.

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  • Understanding of vector notation and operations
  • Knowledge of the dot product in vector mathematics
  • Familiarity with calculating magnitudes of vectors
  • Basic principles of work in physics
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  • Review the definition and calculation of the dot product in vector mathematics
  • Study the concept of vector magnitudes and how to compute them
  • Learn the correct formula for calculating work done by a force
  • Practice problems involving force vectors and displacement in physics
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Students studying physics, particularly those focusing on mechanics, as well as educators looking for examples of vector calculations in work-energy principles.

Justabeginner
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Homework Statement


A force of f= i + 2j- 3k is applied to a particle that moves 10 feet in the direction of i + j. How much work is done?


Homework Equations


W= ||F|| dot product d


The Attempt at a Solution


D= 10 cos 45 i + 10 sin 45 j
D= 5sqrt(2) i + 5 sqrt(2) j
F= i + 2j - 3k

W= ||F|| dot product d
W= sqrt(14) dot product (5sqrt(2)i + 5sqrt(2)j)
W= 5sqrt(28) + 5 sqrt(28)
W= 10sqrt(28)
W= 20sqrt(7)
Is this even right? Thanks!
 
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Justabeginner said:

Homework Statement


A force of f= i + 2j- 3k is applied to a particle that moves 10 feet in the direction of i + j. How much work is done?


Homework Equations


W= ||F|| dot product d

##\| F\|## is a scalar and you can't dot a scalar and a vector.

The Attempt at a Solution


D= 10 cos 45 i + 10 sin 45 j
D= 5sqrt(2) i + 5 sqrt(2) j
F= i + 2j - 3k

W= ||F|| dot product d
W= sqrt(14) dot product (5sqrt(2)i + 5sqrt(2)j)
W= 5sqrt(28) + 5 sqrt(28)
W= 10sqrt(28)
W= 20sqrt(7)
Is this even right? Thanks!

No, it is not correct. You have F and D correct. Look up the correct formula for work.
 

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