Lec35 - Rigid Body 3D Kinematics (Examples)

Correction: at 16:58, the square (i.e. power of 2) was mistakenly left off of the omega_0 factor in the angular acceleration for A. This was immediately corrected in the boxed final answer written immediately afterward.

[@sanyamjain1053]

Amazing content i have not enough words how calmy and clearly u explained the concept.....you deserve million of hearts.............

[@tuhinsuryachakraborty]

the only playlist properly explaining space motion analysis of rigid bodies

[@manostsistrakis8241]

Thank you very much. That was a tremendous help for me. I used to get very confused at calculating the acceleration.

[@adrienlenud]

Thank you very much, out of all the videos I watched this and lec 34 were the only one who made me understand the topic! Thanks!

[@ahmadakmalbinabdmanan6382]

Just wanted to say thanks to you I got to understand this topic in about 30 minutes.

[@ugurcanyardim]

17:15 isn't it alfa(body) = 2 w(secondary) w(primary) i instead of alfa(body) = 2 w(primary)^2 i

[@eyadooi7203]

Great explanation! A direct way to find the acceleration would be taking O and P directly, knowing that the displacement vector from O to P is 3k only. 50:30

[@JosephDT]

In this case you can apply the equations directly between points P and O - the velocity and acceleration equation - since point P is rotating about a fixed point O. Simplifies a lot; otherwise great demo

[@abdulrahman-bc3yj]

thanks alot
Iam just confused, how did you realize that w1 is the relative omega between the body and the secondary and is not the omega of the body.
In other words, how could I know from the question if this omega is for the body or the relative, because it doesn't seem to be clear from the picture

[@Gray-cx9pp]

is there a specific reason for q1 part C that you take point P with respect to G? trying the problem myself first, I thought it'd be easier to take P with respect to D as we determined point D to have zero velocity and subsequently zero acceleration. I got the same answer for point P velocity when taking P with respect to D but my answer for acceleration of point P (again with respect to point D) did not match yours.
regardless, thanks for the video. makes the struggle through Dynamics a little bit easier haha.

[@wakeelmohammed2473]

Thank you Sir, I am so cleared after your sign convention method.

[@IzzuddinAsj]

may i know which textbook you are using?

[@scotreck]

Bedford & Fowler, 5th ed.

[@cem4724]

Thank you for the videos they are really helpful but I had a question I couldn't figure out even after watching the previous lecture. For G to P, at 18:45, why is Wa used instead of the relative angular velocity of P about G? Isn't the rotation of the coordinate system accounted for in Vg?
My intuition was that to find relative motion about a point you basically use a referance frame that keeps said point stationary. If we use Wa what is the point of including Vg into the equation? Why not just use Wa cross the position vector of P relative to O?
EDIT: I corrected the time stamp!

[@scotreck]

G and P are on the same rigid body with no additional rotational motion, so that relationship between v_P and v_G is the one that relates velocities for two point on a rigid-body. The rotation for the disk (omega_A) is the relative rotation between ANY two points on the disk, which is true for any rotation of a rigid body. That is, omega_A is the rotation rate of the disk about G, is the relative angular velocity of P about G (as you suggest), AND is the relative angular velocity of G about P!

[@gayanmadusanka7380]

angular velocity*angular velocity=angular acceleration is that correct....if that statement was wrong ,that equation become wrong as well
(wb*wa/b =(angular acceleration of a))

[@helloig5686]

Where are these questions from

[@diprobanerjee3664]

Hey Scott could you make video solving some examples on 3d kinematics with 3 rotations instead of two? Like a tertiary axis rotating wrt secondary and secondary wrt primary? It would be very helpful. Thanks for your efforts! Much Appreciated.

[@bassman5312]

wht kinda of pens do you use?

[@scotreck]

Pilot G-Tec-C4. They are the best!

[@MegaMirza75]

love your explanation

[@batuhaniyiis3953]

clear voice thank you

[@abdul0222]

Thank you so much sir 🙏🙏

[@beeobama6091]

dude just do these digitally, way neater

[@scotreck]

Agreed! I am moving to working on a tablet for some course material. However, there is something nice and irreplaceable about the tangible pen and paper when doing engineering mechanics.

[@ignatiusjacquesreilly70]

@@scotreck I vote in favor of keeping the pens. Sure, they're not quite as "neat" but for some reason I don't like reading the writing on tablets.