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mybrohshi5
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Homework Statement
A bird of mass 0.5kg is flying near to a building which is 35.0m tall. Take the direction AWAY FROM THE BUILDING to be the +x direction and take UP to be the +y direction. At some instant in time, the bird has an x velocity of +20m/s and a y velocity of -14m/s. At this same instant the ird is located 8 m from the building and 5 m below the roof (30 m above the ground).
What is the angular momentum of the bird about the line along the edge of the roof at this instant in time?
The Attempt at a Solution
Ok so to start of the answer is (-6.0 kg m2/s) k
I am not sure how to get it but this is what i tried.
I used the cross product of this matrix
...I...J
r|...8...(-5)
F|...20...-14
(ignore the dots they were the only way i could line up everything like the matrix i drew :)
so (8)(-14) - (20)(-5)
= -12 kgm2/s in the k direction
Can anyone help me with what i am doing wrong or how to do this correctly?
It was a problem on a test i just took last week and i really want to know how to get the right answer.
Thank you