Rotational Forces on a Hollow Cylinder

AI Thread Summary
To model the rotational speed of a hollow cylinder fixed on a horizontal axle with a tangential force applied, the moment of inertia (I) is crucial. The relevant formula for a cylindrical shell is I = MR^2, where M is the mass and R is the radius. The relationship between torque, moment of inertia, and angular acceleration can be expressed as torque = I * angular acceleration. The mass of the cylinder can be calculated using the formula mass = π * r² * l * ρ. Understanding these equations will help in determining the angular acceleration and rotational speed of the cylinder.
Ben Reynolds
Messages
3
Reaction score
0

Homework Statement


I am trying to model a hollow cylinder of known radius r, length l and density rho.
The cylinder is fixed on a horizontal axle along its longest axis (l) and will have a force F applied tangentially to its surface and perpendicular to its axis, with negligible frictional forces acting between it and the axle.
What equations could I use to model the speed of its rotation?

Homework Equations


Mass = pi*r2*l*rho
Some equation involving moments, potentially?
I am a mathematician and have little work on angular velocity, so I apologise for the trouble.

The Attempt at a Solution


I have attempted to find a relevant equation but all searches gave either inapplicable scenarios or equations quoted ad verbatim with no clarification to notation.
 
Physics news on Phys.org
Do you know about moment of inertia... how it is defined, the formula for the MoI of a cylinder, its use in angular acceleration...?
 
Okay, so I have found the equation I = MR^2 for a cylindrical shell of negligible width being rotated along its long axis, which is close to what I'm looking for. However, I would not know how to include such an equation in finding angular acceleration.
 
Ben Reynolds said:
Okay, so I have found the equation I = MR^2 for a cylindrical shell of negligible width being rotated along its long axis, which is close to what I'm looking for. However, I would not know how to include such an equation in finding angular acceleration.
It's very like the linear equation: torque about axis = moment of inertia about axis * angular acceleration about axis.
 
haruspex said:
It's very like the linear equation: torque about axis = moment of inertia about axis * angular acceleration about axis.

That's perfect, thanks!
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanged mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top