These are not long enough for that hight

yes

I would say not. The ramps would need to be much longer to allow a car to roll up to that height.

No, the approach angles at the top and bottom would be too great and parts of the car would be damaged. IF you were loading the car onto a trailer that has a deck height of less than 24 inches above ground, it would probably be ok

I load 2 to 3 cars a day but not on a semi my car trailer is only 24" off the ground not 4 ' . check the lolad rating on the one your interested in if its 5000 lb i would say yes check you vehicle gross .

Have never done that but I load cars on trailers with them with no problems

container will be to high, will need longer ramps or a loading dock

10000 pound rating is strong for small to med cars but I only use these onto a trailer that is 22 inches off the ground so the angle isn't so steep. There is a set of 2 steel pins that hold the tops of these Ramps to the bed of the trailer. I drive my riding mower up these and they are very sturdy..I weigh 260lbs and the mower is around 600 lbs. So 860 lbs and no problem. ALWAYS secure ramp tops to trailer bed..some guys use ratchet straps from ramp to frame of trailer. I keep the angle of ramp around 10 degrees...NO MORE THAN 12 degrees.

No it’s 3000 lbs per ramp. They are solid but I don’t know that I would drive a car or truck on them. Perfect for large UTVs though.

No it's 3000lb per ramp. 6000lb is for the two of them together. Hope this helps.