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May 6, 2016

# Homework Help: PHYSICS

Posted by Matt on Thursday, February 17, 2011 at 7:13pm.

A copper vat is 10 m long at room temperature (20 degrees C). How much
longer it is when it contains boiling water at 1 atm pressure?

Air in a balloon does 50 J of work while absorbing 70 J of heat. What is
its change in internal energy?

A bottle containing 3 kg of water at a temperature of 20 degrees C is placed
in a refrigerator where the temperature is kept at 3 degrees C. How much heat is transferred from the water to cool it to 3 degrees C?

Aluminum is melted during the recycling process.
(a) How much heat must be transferred to each kilogram of aluminum to bring it to its melting point, 660 degrees C, from room temperature, 20 degrees C?
(b) About how many cups of coffee could you make with this much heat?

A piston contains 1m^3 of helium at a temperature of 250 K and an absolute pressure of 1.0kPa. The following changes are made in sequence:
(a) First the volume of the piston is decreased to 0.2 m^3 while the temperature is kept constant, what is the pressure of the gas?
(b) Taking the gas after process (a) has been carried out. Now the volume of the gas is kept fixed at 0.2 m^3 but the temperature of the gas is raised to 500K. What does the pressure of the gas become?
• PHYSICS - drwls , Thursday, February 17, 2011 at 7:43pm