A 22000 kg subway train initially traveling at 10.0 m/s slows to a stop in a sta

Question

A 22000 kg subway train initially traveling at 10.0 m/s slows to a stop in a station and then stays there long enough for its brakes to cool. The station's dimensions are 65.0 m long by 20.0 mwide by 12.0 m high.

Part A A 22000 kg subway train initially traveling at 10.0 m/s slows to a stop in a station and then stays there long enough for its brakes to cool. The station's dimensions are 65.0 m long by 20.0 m wide by 12.0 m high Assuming all the work done by the brakes in stopping the train is transferred as heat uniformly to all the air in the station, by how much does the air temperature in the station rise? Take the density of the air to be 1.20 kg/m 3 and its specific heat to be 1020 J/(kg·K) Submit My Answers Give Up Provide Feedback Continue

Explanation / Answer

Mass of train=22000kg

Velocity=10m/s

Kinetic energy of train=(1/2)*22000*10²=1100000 Joules

Volume of air=65*20*12=15600 m³

Density of air=1.2 kg/m³

Mass of air=15600*1.2=18720 kg

18720*1020*(change in temperature)=1100000

Change in temperature=1100000/(18720*1020)=0.058 K

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.