A ladder is placed along a wall such that its upper end is touching the top of the wall. The foot of the ladder is 10 ft away from the wall and the ladder is making an angle of $$60^{0}$$ with the ground. When a man starts climbing on it, it slips a ?->(Show Answer!)

1. A ladder is placed along a wall such that its upper end is touching the top of the wall. The foot of the ladder is 10 ft away from the wall and the ladder is making an angle of $$60^{0}$$ with the ground. When a man starts climbing on it, it slips and now ladder makes an angle of 30° with ground. How much did the ladder slip from the top of the wall?

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By: anil on 05 May 2019 02.28 am

Given : BC is the initial position of the ladder, and DE is its final position. So, DE = BC (as both are the same ladders) To find : CD = $$x=?$$ Solution : In $$ riangle$$ ABC, => $$cos(60^circ)=frac{AC}{BC}$$ => $$frac{1}{2}=frac{10}{BC}$$ => $$BC=10 imes2=20$$ Thus, $$DE=BC=20$$ Similarly, in $$ riangle$$ ADE, => $$cos(30^circ)=frac{AD}{DE}$$ => $$frac{sqrt3}{2}=frac{x+10}{20}$$ => $$x+10=10sqrt3$$ => $$x=10(sqrt3-1)$$ => $$x=10 imes0.732=7.32$$ $$ herefore$$ The ladder slipped 7.32 ft => Ans - (C)

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MCQ->A ladder is placed along a wall such that its upper end is touching the top of the wall. The foot of the ladder is 10 ft away from the wall and the ladder is making an angle of $$60^{0}$$ with the ground. When a man starts climbing on it, it slips and now ladder makes an angle of 30° with ground. How much did the ladder slip from the top of the wall?....

MCQ-> Cells are the ultimate multi-taskers: they can switch on genes and carry out their orders, talk to each other, divide in two, and much more, all at the same time. But they couldn’t do any of these tricks without a power source to generate movement. The inside of a cell bustles with more traffic than Delhi roads, and, like all vehicles, the cell’s moving parts need engines. Physicists and biologists have looked ‘under the hood’ of the cell and laid out the nuts and bolts of molecular engines.The ability of such engines to convert chemical energy into motion is the envy nanotechnology researchers looking for ways to power molecule-sized devices. Medical researchers also want to understand how these engines work. Because these molecules are essential for cell division, scientists hope to shut down the rampant growth of cancer cells by deactivating certain motors. Improving motor-driven transport in nerve cells may also be helpful for treating diseases such as Alzheimer’s, Parkinson’s or ALS, also known as Lou Gehrig’s disease.We wouldn’t make it far in life without motor proteins. Our muscles wouldn’t contract. We couldn’t grow, because the growth process requires cells to duplicate their machinery and pull the copies apart. And our genes would be silent without the services of messenger RNA, which carries genetic instructions over to the cell’s protein-making factories. The movements that make these cellular activities possible occur along a complex network of threadlike fibers, or polymers, along which bundles of molecules travel like trams. The engines that power the cell’s freight are three families of proteins, called myosin, kinesin and dynein. For fuel, these proteins burn molecules of ATP, which cells make when they break down the carbohydrates and fats from the foods we eat. 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MCQ-> Read the passage carefully and answer the questions given at the end of each passage:We now come to the second part of our journey under the sea. The first ended with the moving scene in the coral cemetery which left a deep impression on my mind. I could no longer content myself with the theory which satisfied Conseil. That worthy fellow persisted in seeing in the Commander of the Nautilus one of those unknown servants who returns mankind contempt for indifference. For him, he was a misunderstood genius who, tired of earth’s deceptions, had taken refuge in this inaccessible medium, where he might follow his instincts freely. To my mind, this explains but one side of Captain Nemo’s character. 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MCQ-> Before the internet, one of the most rapid changes to the global economy and trade was wrought by something so blatantly useful that it is hard to imagine a struggle to get it adopted: the shipping container. In the early 1960s, before the standard container became ubiquitous, freight costs were I0 per cent of the value of US imports, about the same barrier to trade as the average official government import tariff. Yet in a journey that went halfway round the world, half of those costs could be incurred in two ten-mile movements through the ports at either end. The predominant ‘break-bulk’ method, where each shipment was individually split up into loads that could be handled by a team of dockers, was vastly complex and labour-intensive. Ships could take weeks or months to load, as a huge variety of cargoes of different weights, shapes and sizes had to be stacked together by hand. Indeed, one of the most unreliable aspects of such a labour-intensive process was the labour. 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