Work Energy And Power Question 291

Question: An engine is hauling a train of mass M kg on a level track at a constant speed v m/s. The resistance due to friction is $ fN/kg $ . What extra power must the engine develop to maintain the speed up a gradient of h in s :

Options:

A) $ \frac{mghv}{s} $

B) $ \frac{mghs}{v} $

C) $ Mghvs $

D) zero

Show Answer

Answer:

Correct Answer: A

Solution:

[a] Extra power, $ P = mg sin \theta \times v $

$ =Mg\times \frac{h}{s}\times v=\frac{Mghv}{s}. $



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