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An engine draws a train up an incline of 1 in 100 at the rate of 36 kmh-1. If the resistance due to friction is 5 kg wt per ton, find out the power of the engine. Mass of train and engine is 100 metric ton. |
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Answer» Given : m = 100 metric ton = 100 × 1000 kg Total force of friction, f1 = 100 × 5 = 500 kg wt = 500 × 9.8 N = 4900 N \(sin\,θ=\frac{1}{100}\) Suppose, f2 = Downward force on the train = component of its weight acting in downward direction parallel to the inclined plane = mg sin θ = 100 × 1000 × 9.8 × \(\frac{1}{100}\) = 9800 N When F be the total force against which engine has to work, then F = f1 + f2 = 4900 + 9800 = 14700 N v = velocity of train = 36 kmh-1 = 36 × \(\frac{5}{18}\) ms-1 = 10 ms-1 ∴ Power of the engine, is given by P = F × v = 14700 × 10 = 147000 watt = 147 kW. |
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