Physics help KE, W, PE

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  • #1
cyberdx16
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https://mywebspace.wisc.edu/dxiong4/physics%201.bmp?uniq=-w1zg99 [Broken]

for part b i am to find work of gravity, and to do so what i did was

mass*gravity*cos 22*distance(12) to get 436.14, but it seems that it is wrong

i've tried mass*gravity*distance (12)=470.4 and still is not the correct answer, can someone plz explain to me what i am doing wrong? thx
 
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  • #2
cristo
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https://mywebspace.wisc.edu/dxiong4/physics%201.bmp?uniq=-w1zg99 [Broken]

for part b i am to find work of gravity, and to do so what i did was

mass*gravity*cos 22*distance(12) to get 436.14, but it seems that it is wrong

i've tried mass*gravity*distance (12)=470.4 and still is not the correct answer, can someone plz explain to me what i am doing wrong? thx

Check the red part; you want the component of the weight acting parallel to the slope.
 
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  • #3
HallsofIvy
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Conversely, you want the upward component of displacement-
[itex]sin(\theta)[/itex], not [itex]cos(\theta)[/itex]. It's the same as cristo's point.
 

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