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HW Assignement 3
Verfasst: 06.11.2016, 15:24
von smefix
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
Re: HW Assignement 3
Verfasst: 07.11.2016, 17:18
von randomuser
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
Re: HW Assignement 3
Verfasst: 08.11.2016, 18:11
von Chris
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
Re: HW Assignement 3
Verfasst: 08.11.2016, 23:47
von smefix
randomuser hat geschrieben: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 calculated the center of mass for the wedge and the bar separately. If you look at page 5 you can see, that I used
for the wedge. The center of mass should be correct.
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.
Re: HW Assignement 3
Verfasst: 08.11.2016, 23:52
von smefix
Chris hat geschrieben: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
The total mass is
and