Rigid body Newton’s law homework

[Pipsqueakalchemist]

Homework Statement

Problem and solution below

Relevant Equations

F = ma
Moment equation

For this problem I know how to get the answers but I have a few things I’m not 100% sure about. First how do we know that the rod is experiencing centripetal motion? Second, when using moment about point G how do we know that the angular acceleration is equal to zero? And third the radius is 0.4 because the two ends of the rod are in motion with radius of 0.4 right?

 

[BvU]

1. Because 200 N + 300 N > mg
2. Because the ropes fix the angle of the rod $\rightarrow$ it can't rotate around G
3. Yes

I know how to get the answers

yea, because it seems you have a solutions manual at your disposition ? PF rules in fact require you to post your own attempt at solution

 

[Pipsqueakalchemist]

Well my test is on Monday and I still have another 10 question in the problem set. I can’t afford to get stuck on every single question.

 

[BvU]

I see. Was my reply in #2 ok with you ?

$\$

 

[Pipsqueakalchemist]

Yea I guess I see it. Since the bar isn’t rotating around point G or around any point on the bar itself so regardless of which point I chose the angular acceleration will always be zero right?

 

[Lnewqban]

 

[Pipsqueakalchemist]

Hey you commented on my other post. The one with the tipping cabinet. Do you mind looking at it because I still have some confusion.

 

[Lnewqban]

Hey you commented on my other post. The one with the tipping cabinet. Do you mind looking at it because I still have some confusion.

Me too.

 

[Pipsqueakalchemist]

Lol, yea Ik the signs don’t make sense