Have listened to countless professor try to explain the cross-product and I never could understand it. You just explained it with (I-J-K-I-J) in 10 seconds.
Thanks Colin. I'm reviewing some old material for my Comprehensive exams for my PhD program. I was reviewing Meriam & Kraige's Engineering Dynamics where they suggest graphical vector methods (brutal). I knew I first learned it another way, once upon a time. I couldn't find my notes though. So I stumbled across this and it all came back! Thanks for teaching dynamics the right way.
+kwmountainbikers Thanks mountain biker. I cannot understand the graphical solution as well as the vector representation and it seems prone to errors. Too much trigonometry.
Hello Mr. Selleck - outstanding Physics Mechanics and Kinetics Series you have done here, thank you! One thing: if you can please post the problem statement on the screen, then *pause it* for us to examine the problem, then zoom in to solve the problem, that will help. (As it is, I know you are eager to zoom in -- but that negates the problem statement display at 6:38ff, 9:59ff, and 12:52ff. I am viewing on an iPhone 6S in Landscape mode, so if there is any special limitation of iOS 10 to view the entire dimensions of your lecture please let me know; but I have never seen any limitations for iPhone running iOS 10 to display full dimensions on a web page or a video player.) Thank you and regards, Bill W
My question stems from: In the second example you choose to use A->B (4th quadrant) and thus Rb/a but in the 3rd example you choose C->B (2nd quadrant) and thus Rb/c , how do i make this choice correctly in other examples?
The best way to do this is to write the subscripts correctly. e.g., Va = Vb + w cross Ra/b. From left to right the subscripts read a, b, a/b. There is an order to it: A B A/B. Once you do this correctly, all will be well. You can also write Vb = Va + w cross Rb/a. To envision what Va/b is - you are standing on B and looking at A so Va/b means the velocity A appears to have if you are standing on (and moving with) B.
In the last problem, for the velocity of B shouldn't your I and J components be switched? Or did you already account for the cross product and change them?
+Micah Schumaker Sorry for the late reply. The velocity of B components are correct since the velocity of B is perpendicular to the link AB, which is at 60 degrees in the first quadrant. So Vb is 30 degrees away from the negative x axis. I could have written -cos30 i + sin 30 j.
Sir , Thank you so much for the awesome videos , but I think there is a mistake in the last example Vc should equal 1.64 m/s and Wbc should be 11.76 rad/sec
Have listened to countless professor try to explain the cross-product and I never could understand it. You just explained it with (I-J-K-I-J) in 10 seconds.
Glad to be of help!
Thanks Colin. I'm reviewing some old material for my Comprehensive exams for my PhD program. I was reviewing Meriam & Kraige's Engineering Dynamics where they suggest graphical vector methods (brutal). I knew I first learned it another way, once upon a time. I couldn't find my notes though. So I stumbled across this and it all came back! Thanks for teaching dynamics the right way.
+kwmountainbikers Thanks mountain biker. I cannot understand the graphical solution as well as the vector representation and it seems prone to errors. Too much trigonometry.
So helpful M9, you truly are da real MVP
straight fire
Great Explanation! This is something that I always struggle to explain and you have given a really awesome discussion to the topic.
Excellent video, sir. I'm studying for my FE exam. Your explanation was simple and easy to understand.
Thank you.
Hello Mr. Selleck - outstanding Physics Mechanics and Kinetics Series you have done here, thank you! One thing: if you can please post the problem statement on the screen, then *pause it* for us to examine the problem, then zoom in to solve the problem, that will help. (As it is, I know you are eager to zoom in -- but that negates the problem statement display at 6:38ff, 9:59ff, and 12:52ff. I am viewing on an iPhone 6S in Landscape mode, so if there is any special limitation of iOS 10 to view the entire dimensions of your lecture please let me know; but I have never seen any limitations for iPhone running iOS 10 to display full dimensions on a web page or a video player.) Thank you and regards, Bill W
@MicahScumaker: The i and j components are correct. The vector Vb is 30 degrees from the x axis in the II quadrant and sin 60 = cos 30.
u r awesome , this video almost save my life
Thank you so much for making this awesome video :D I hope can find more example problems from your channel :)
Thank you so much for these problems!! They really helped alot!!
You're very welcome!
Thanks for this video and the whole series. I wish that I had found it sooner.
Always Learnin' You are welcome.
you cut the question in half. i can see your diagrams but never the question . not sure why. other than that you are a great instructor
Thank you so much! This has helped me a lot!! :))
You're welcome!
Thanks Colin,
It was very useful to me :)
You are most welcome.
in last question how you got (Omega BC)= 45??
When considering R what is the best way to decide whether i should use Rb/a or Ra/b ; seems to switch looking around at different examples.
My question stems from: In the second example you choose to use A->B (4th quadrant) and thus Rb/a but in the 3rd example you choose C->B (2nd quadrant) and thus Rb/c , how do i make this choice correctly in other examples?
The best way to do this is to write the subscripts correctly. e.g., Va = Vb + w cross Ra/b. From left to right the subscripts read a, b, a/b. There is an order to it: A B A/B. Once you do this correctly, all will be well. You can also write Vb = Va + w cross Rb/a. To envision what Va/b is - you are standing on B and looking at A so Va/b means the velocity A appears to have if you are standing on (and moving with) B.
it is great for review
Thank you Dr so much it is really helpful
You're welcome!
if omega is clockwise , will it be negative k in that case?? because all your example shows anticlockwise omega. Thank you
+Shakir Tahiri What time stamp do you refer to?
In the last problem, for the velocity of B shouldn't your I and J components be switched? Or did you already account for the cross product and change them?
+Micah Schumaker Sorry for the late reply. The velocity of B components are correct since the velocity of B is perpendicular to the link AB, which is at 60 degrees in the first quadrant. So Vb is 30 degrees away from the negative x axis. I could have written -cos30 i + sin 30 j.
legend
Sir , Thank you so much for the awesome videos , but I think there is a mistake in the last example
Vc should equal 1.64 m/s
and Wbc should be 11.76 rad/sec
There is a mistake, but the answers I get are Wbc is 6.79 rad/sec and Vc is -1.2 m/s.
it is better to have nice letters, very difficult to recognize. a important explanation.
Thank you
You're welcome!
Romeo Artist
i thout this was sao 16.5