☰ Contents · Physics

Fuel and the first law of thermodynamics

Lessons 22–23 · 2 lessons · P. Habibullayev, A. Boydedayev, A. Bahromov, K. Suyarov, J. Usarov, M. Yuldasheva. Physics Grade 9, revised and expanded 3rd edition. G‘afur G‘ulom Publishing House, Tashkent, 2019
Answers are for parents and teachers.
1
Burning 15 kg of dry wood (q = 10 MJ/kg) gives Q (MJ):
2
How many kg of alcohol (q = 29 MJ/kg) give 87 MJ when burned?
3
A gas receives 900 J of heat and does 400 J of work. ΔU (J)?
4
250 J of work is done on a gas compressed adiabatically. What is ΔU?
5
Why does a bicycle pump heat up when used quickly?