All Questions
83 questions
0votes
1answer
38views
Problem regarding torque [closed]
I am unable to find a correct answer to this. X and Y are two forces (as shown in the figure below) 400 cm apart. O is the point midway between X and Y. P is a point along X. Calculate the sum of ...
0votes
0answers
83views
Horizontal Force - Tilted Disk (Rolling Quarter) [closed]
https://physics.stackexchange.com/q/72610 Can someone unpack the origin of this horizontal force for me a bit? I can see a torque about the center of mass from the static friction $ mR\Omega^2 r \sin \...
- 121
3votes
1answer
151views
How to describe the motion of inertial particles in non-inertial frames?
Imagine a rotating observer represented by the basis $B = \{\mathbf{\hat r}, \boldsymbol{\hat \varphi}\}$. This observer wants to describe the movement of a particle moving on a straight line ($\...
- 1,821
0votes
1answer
67views
Euler Angles Representation
I have an exam in two days in classical mechanics and I've encountered a question about Euler Angles that I did not completely understand: The question goes like this: Given two similar bodies as ...
- 33
1vote
2answers
178views
Why doesn't centripetal force act at the com of an object?
A rod is connected by one end to a vertical axis by a hinge and is free to swing outwards when rotated about the vertical axis. The locus of the rod traces out a cone shape. What is the angle of the ...
3votes
1answer
253views
Doubt in rotational work-energy theorem
This is a question on work-energy theorem in rotational motion with its answer for the first part of the question. Here, I have a doubt about why is the book taking the translational work done by the ...
- 97
1vote
1answer
142views
Moment of Inertia of Cylinder through horizontal axis [closed]
Regarding moment of inertia (MOI) of a solid cyclinder, I want to calculate the MOI through the horizontal axis (central diameter) which is the 2nd diagram in the figure: I want to do so by using the ...
- 387
1vote
1answer
74views
Doubt regarding the moment of inertia of a rod [closed]
In this system, I am calculating kinetic energy as: $$ T = \frac{1}{2}I_{O}w_{O}^2 + \frac{1}{2}I_{G}w_{bar}^2 + \frac{1}{2}v_{G}^2 $$ Being G the center of mass of the rod AB. Note: A is not fixed. ...
2votes
2answers
134views
Angular velocity calculation
The statement of the exercise is as follows: The system in the figure consists of a disk of radius R and a bar AB of length 4R, with no slipping between them. The disk rolls and slides on the floor, ...
0votes
0answers
105views
Centripetal acceleration and tangential velocity for object that rotate and revolve in same time?
Right picture is two turn tables on of top of the other, smaller turn table is connected with shaft to bigger one so it rotate around itself and in same time "revolve" around center of ...
- 722
1vote
1answer
57views
Trajectory of Instantaneous center of rotation of a disc performing both rotational and translational motion [closed]
I am posting the specific problem I am dealing with for reference and then explain the part I am confused with. My Understanding and approach to the problem I identified that in the ground frame the ...
1vote
2answers
627views
Axis of rotation of a spool unwinding and falling under gravity
There is a problem that asks for forces that apply torque around the axis of rotation on a spool of string that falls and unwinds under gravity. The spool falls straight down with a vertical string. ...
- 71
0votes
2answers
91views
A question regarding momentum of inertia of L-shaped bar [closed]
I have trouble deriving moment of inertia $\Theta_A$ of the bar rotating around the point A shown in the image. The answer of the problem says: $\Theta_A=\frac{m}{3}\frac{a^2}{3}+\left[\frac{(2a)^2}{...
0votes
1answer
79views
Doubt on angular momentum formula
When using the conservation of angular momentum in collisions like the one in the following image. Where there is a hoop of radius ${R}$ that is resting on a horizontal frictionless surface and a ...
- 17
0votes
2answers
51views
Query regarding parallel axis theorem
Suppose there are two points at (4,0) and (-4,0) each of mass 1 kg and the origin is (0,0). The rotational inertia of the combined system is 32kg.m^2. But if we shift the axis of rotation to left by 2 ...
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