Basic Statics/Dynamics System of Equations (help)

AI Thread Summary
The discussion revolves around a model vehicle powered by a twisted rubber band, focusing on understanding the loads through its member bodies. The user has created free body diagrams and outlined equations, noting that static forces and moments sum to zero in the vertical direction, while horizontal acceleration is governed by the equation sum of forces equals mass times acceleration. They express confusion over having nine equations and only six unknowns, suggesting a potential over-specification in their system. A suggestion is made to solve the equations using matrix methods to identify any algebraic mistakes. The user seeks a sanity check on their logic and equations to ensure accuracy.
kroq
Messages
6
Reaction score
0

Homework Statement



Hi there, I'm working on a simple model vehicle (powered by a twisted rubber band) applying torque to a drive wheel. I just want to understand the loads going through the member bodies.

I've mocked up the enclosed free body diagrams and attempted to outline the systems of equations. Can I get a sanity check on my logic.

The static considerations sum to zero for forces and moments in the vertical direction.
The vehicle will accelerate horizontally as its powered by the band. Sum of forces equal ma. Sum of moments equal I•alpha.

A sanity check would be appreciated. It's not solving out correctly, and it seems weird to have a system of 9 equations and 6 unknowns.

Homework Equations



See jpeg.

The Attempt at a Solution



See jpeg.
 

Attachments

  • systemofequations.jpg
    systemofequations.jpg
    16 KB · Views: 524
Physics news on Phys.org
Havn't studied your jpeg but if your equations are all linear then you should only need the 6 equations with the 6 unknowns. You might be over-specifying. If you think it's an algebraic mistake maybe you could try solving via matrix (6x6^-1 * 6x1)?
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
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 hanging 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