That depends on what it is carrying. . .you definitely need to consult a structural engineer for this information, and having the original set of plans to show him will help. FYI. . .28 feet is a VERY long clear-span for any type of beam.
Use a steel beam.. That would be code.. steel w10x15 (50ksi) I beam.
big one
The steel reinforcement used will depend on several factors. Column length, beam length, and the column and beam cross section all depend on how much steel will be needed.
It depends on the type of beam, the material, whether it is a bridge span or cantilever, the allowable deflection and safety margin needed. We need a lot more data on the application.
The size of timber used in the post and beam building method is variable depending on the project. Some version will use entire logs up to 26 meters in length.
Vermont Timber Works has an extensive web site on timber frames and post & beam construction.
A beam is a crossbar of a balance, a large piece of timber or iron, a horizontal timber of a building, or a ray or collection of rays of parallel light.
Stake, timber, beam, board, plank, log...
A joist, either floor or ceiling are the boards that go across the building and tie the walls together. A timber joist would be a rough sawn beam. Basically a tree that has been squared up.
The distance a beam of light would travel in 7500 seconds can be calculated by multiplying the speed of light by the time traveled: 3.00 x 10^8 m/s * 7500 s = 2.25 x 10^12 meters. The beam of light would travel 2.25 trillion meters in 7500 seconds.
The word you seek is beam.
About 5metres(16') but would have to be stress graded timber.
Kilograms measure mass, or weight. Meters measure distance, or length. So there is no answer for the question as asked. Consider: 69 meters of thread would weigh a tiny fraction of what 69 meters of steel I-beam would weigh. It does depend. You have to specify.
Grams
Make, model and year would help.
High beam headlights can illuminate anywhere from 30 meters to 150 meters ahead of the car. This is 98 feet to 492 feet away.