A 20% efficient real engine is used to speed up a train from rest to 7.0 m/s. An ideal (Carnot) engine using the same cold and hot reservoir would accelerate the same train from rest to a speed of 8.0 m/s using the same amount of fuel. The cold reservoir is at 290 K. Find the temperature of the hot reservoir. Hint: Think work energy theorem.

Question

A 20% efficient real engine is used to speed up a train from rest to 7.0 m/s.  An ideal (Carnot) engine using the same cold and hot reservoir would accelerate the same train from rest to a speed of 8.0 m/s using the same amount of fuel.  The cold reservoir is at 290 K.  Find the temperature of the hot reservoir.  Hint:  Think work energy theorem.