1 the resistance of water to an oar in a rowboat limits the oar's efficiency to 0.450of the rower does 145 J of work on the oar with each stoke how much useful work is done by the oar? 2) a jack requires 808 J of work to be done in raising a load and ideally would do this amount of useful workhowever inteanl friction reduces the jack's effieciency to 0.625How much useful work is done by the jack?3) a large crane lifts a 25000 kg mass in the airthe amount of work that must be done by the crane's lifting components is 2.2 mulitiply 10^7 J if the efficiency of the crane is 22 percent how much useful work is done on the mass?
Aluminium is expensive as far as I knowI would do the costing on the aluminium firstAlso aluminium is a little weaker so you'll need a thicker sheetI would go with galvanised.
Aluminum is not as strong as steel, so you would need a thicker pieceAlso you need to select the aluminum alloy to match the application, there are many different alloysAnd Al is more expensive than steel, so you have to look at your cost budgetGalvanized will not rust, so your only reason is looks? Not a decision for you to make, but for the customer.
Aluminium needs to be 50% thicker than steel for the same strength.
1If the efficiency is 0.45 and the total output is 145 J, then0.45 100x/145 x 145/100 0.45 x 65.25 J Let's see if you can solve the rest of the problem by yourselfNote that they are similar to the first!
Which has better songs - Number Of the Beast Which has better riffs - British Steel Which has better solos - Number of The Beast Which has better vocals - Number of the Beast Which has a cooler cover - Number of the Beast Which do You prefer - This is a real thinker, almost like Sophies Choice Metal editionBut I have owned Number and the Beast longer than I have owned British SteelSo I go with Iron Maiden Both albums get a perfect 10 because they deserve it, both have great musicianship and both have great vocals
