Analytic mechanic, disk and rod

In summary, the conversation discusses a kinematics problem involving a rolling rod and disk, and the relation between velocities Va and Vohm. The problem involves defining more variables and writing equations to solve for the desired information. However, the professor does not allow for a mathematical formulation.
  • #1
loreberto911
4
0
< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown >

?temp_hash=6ae0d015ab67fa1fdbc0d76c05711e87.jpg

A rod rolls without creep. And the disk rolls without creep on Q. The rod can just moves on y. Which is the relation among Va and Vohm?
Va= velocity in A
My resolution:
in Q we know that velocity is zero.Q is also the instant rotation center ( disk).so the P point ( disk) is the fastest. How to bound speed in
##\Omega## and Va?
I mean, just seeing the picture, without using the fondant formula of rigid cinematic. I could think it's like the half of Va.
Ps.it's my first article and my english isn't so good, I hope you'll understand anyway.
 

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  • #2
Your picture does not define point P very well. Is it the top of the disk, or is it the tangent point? If it is the tangent point (as I suspect), it is "not the fastest point." The "fastest point" is directly on the top.

This is a kinematics problem, and as such, you need to define some more variables and write the suitable relations among them. Define a variable name for the height of point A, a variable for the distance from A to the tangent point (P?), and the angle of the bar with respect to the horizontal. Then write the equations defining the closed loop from the origin to A to P to the center of the disk to Q and back to the origin; there will be two such equations. These can be solved for what you need.
 
  • #3
OldEngr63 said:
Your picture does not define point P very well. Is it the top of the disk, or is it the tangent point? If it is the tangent point (as I suspect), it is "not the fastest point." The "fastest point" is directly on the top.

This is a kinematics problem, and as such, you need to define some more variables and write the suitable relations among them. Define a variable name for the height of point A, a variable for the distance from A to the tangent point (P?), and the angle of the bar with respect to the horizontal. Then write the equations defining the closed loop from the origin to A to P to the center of the disk to Q and back to the origin; there will be two such equations. These can be solved for what you need.

Thanks for reply,
Point P is tangent, the question that teacher asked to me was "give me a qualitative consideration of velocity in ##\Omega##"
For example the direction, and approximately the entity like "it's 1/3...2/3 of Va". The problem gives me just Va and nothing else. I tried to set problem analytically but professor said no.
 
  • #4
Afraid I can't help you if a proper mathematical formulation is not allowed.
 

1. What is analytic mechanics?

Analytic mechanics is a branch of physics that uses mathematical tools to study the motion and behavior of physical systems. It combines principles from classical mechanics and calculus to develop equations that describe the motion of objects.

2. How do disks and rods play a role in analytic mechanics?

Disks and rods are commonly used as examples in analytic mechanics to illustrate concepts such as rotational motion, torque, and angular momentum. They can also be used to model more complex systems, such as gears or pendulums.

3. What is the difference between a disk and a rod in analytic mechanics?

A disk is a circular object with a radius, while a rod is a straight object with a length. In analytic mechanics, disks are often used to represent objects with rotational motion, while rods are used to represent objects with translational motion.

4. What are some real-world applications of analytic mechanics with disks and rods?

Analytic mechanics with disks and rods can be applied to a variety of real-world systems, such as the motion of planets and satellites, the behavior of gears in machinery, and the movement of pendulums in clocks.

5. How does analytic mechanics with disks and rods contribute to our understanding of physics?

Analytic mechanics with disks and rods provides a mathematical framework for understanding the fundamental principles that govern the behavior of physical systems. It allows us to make predictions and calculations about the motion of objects, and has played a crucial role in the development of many technologies.

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