update: finally finished the project. Mechanical actions did not play out exactly as I wanted but the results are working well. Thanks for all the help so that I could assure the people I made this for that the cable was well under it's rated working tension.
Found a better calculation that looks better graphed out.
Next Problem: I know using a single pulley on an extension spring divides the weight it will hold. But, will 2 pulleys (one attached to the spring) still only divide by 2 since I am still attached only to the beam and the load? (diagram...
I'm looking at using extension springs for safety and support so I tried to plot out the cable tension as the ramp lowers. The tension seems to increase evenly as it lowers and that is not what I thought would happen. Am I missing something? (see attached) Thanks.
Awesome information and thanks for all input. Here is a really bad drawing of how I intend to do the cabling. For the pulleys, I intend to use roller fairleads (unsed on winches). (still need to find a good deal on 2 I-beams for the ceiling. Ramp weight has gotten a little lighter (making it...
graduated HS in 1980. Building a ramp for a semi trailer for my daughter's band. Do not know anything about physics except that they apply and I am concerned that the cable&winch is strong enough to support the load.
(not a physics person so hope my description is clear enough)
bridge mass = 3150 Newtons (center of mass is in center)
length = 5 meters
cable is attached to wall 3 meters straight up from bridge hinge
cable is attached to bridge 3.5 meters from hinge
situation: bridge is...