In the attached files you can find the examples from HW 3 and my solutions.
However I cannot guarantee that the solution is 100% correct 
If anyone finds an error, feel free to tell me 
Note: I made an typing error while calculating the rotational Energy. I have now uploaded the corrected version 
HW3_felix.pdf (2.53 MB)
IntroBiomech_Homework-3.pdf (197 KB)
Hey thanks for your solutions - I think you made an error while calculating the center of mass of the wedge. The x2 coordinate should be 2/3 l - you grouped up rho * b * h * l to form the mass of the body, while it actually is 1/2 * rho * b * h * l
regards
I got a different final center of mass vector… I think you did a mistake when calculating the sum.
How do you get a FG=30N? Shouldn’t it be 80/3 N? you have a totalmass of 8/3 kg. I not quite sure about it, so maybe you could have a look at yours as well.
regards
I calculated the center of mass for the wedge and the bar separately. If you look at page 5 you can see, that I used \frac{\rho \cdot b \cdot h \cdot l}{2} for the wedge. The center of mass should be correct. \frac{2 \cdot l}{3} is only correct if the wedge was rotated by 180°. If you look at the wedge, most of its mass is on the left side.
The total mass is \frac{3 \cdot \rho \cdot l \cdot b \cdot h}{2} and \rho=2000 \frac{kg}{m^3}