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InterviewSolution
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The mass of a cyclist together with the bicycle is 90 kg. Calculate the work done by cyclist if the speed increases from6km/h to 12 km/h. |
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Answer» Solution :Mass of cyclist together with bike, m = 90 kg. Initial velocity, U = 6km/h = `6x(5//18)` ` = 5//3` m/s Final velocity, `v = 12km//h = 12xx(5//18)` ` = 10//3` m./s Initial kinetic energy `K.E._((i)) = (1)/(2) mu^(2)` ` = (1)/(2)(90)(5//3)^(2)` ` = (1)/(2) (90) (5//3) (5//3)` = 125 J Final kinetic energy `K.E._((f)) = (1)/(2) mv^(2)` `= (1)/(2) (90) (10//3)^(2)` ` = (1)/(2) (90) (10//3) (10// 3)` ` = 500J` THe workdone by the cyclist = CHANGE in kinetic energy = `K.E_((f)) - K.E_((i))` ` = 500J -125 J = 375J` |
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