i need help in statics and dynmics
Experimental Example
Robert J Martinez
The Experiment
Creating a mathematical model using a physical model constructed with house hold objects.
The numbers will vary because in the real world there are various factors to consider that aren't exact. Things like air, the exact coefficient of static friction, the friction from the bar, etc... In other words this is not a controlled environment.
The Experiment
I would be setting up a makeshift pulley that will hold onto a wooden drawer and be attached to a weight. I would be trying to find the tension in the rope while the system is in static equilibrium.
Materials
dog leash
two chairs
weights (3lbs) (5lbs) Equiv: 14kg
& 225kg
wooden desk
wooden escrema
Set up
The second drawer was pulled out so that the system would give a 90 degree angle at the rope along the "pulley"
Free Body Diagrams
Equations
Conversion ratio from pounds to kilograms: 1lb = .453kg
∑F=0
Coefficient of static friction (wood on wood) : 0.25 - 0.5
Acceleration due to gravity 9.81m/s ^2
Results
Able to model the physical system in static equilibrium with 12lbs in the drawer and 10lbs on the weight.
Using the first FBD I was able to construct the first force equation.
I knew that the tensions had to be similar to each other, but I also knew that the results would differ a bit because I don't have a true frictionless pulley.
Results Continued
Sources
http://www.physlink.com/Reference/FrictionCoefficients.cfm
Engineering Statics Mechanics 13th Edition
Thank You!