Physics help KE, W, PE

1. Feb 27, 2007

cyberdx16

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

Last edited by a moderator: May 2, 2017
2. Feb 28, 2007

cristo

Staff Emeritus
Check the red part; you want the component of the weight acting parallel to the slope.

Last edited by a moderator: May 2, 2017
3. Feb 28, 2007

HallsofIvy

Staff Emeritus
Conversely, you want the upward component of displacement-
$sin(\theta)$, not $cos(\theta)$. It's the same as cristo's point.