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Force Vector Magnitude Distance

  • #1

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!
 

Answers and Replies

  • #2
LCKurtz
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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
##\| 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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