PH 161 - Homework 4 - Due Friday, May 2
Ch. 4.
Questions: 4 and 9
Problems:
5. For this problem, it seems that you would need to know how much water
is in the kettle, but you don't. All you need to know is the amount of energy
required to heat some amount of water by a certain temperature, compared
to the amount of energy required to convert that same amount of water to
steam. Think about it!
8 (p 122). This is a reasonable model for planned OTEC ("Ocean Thermal Energy
Conversion") facilities except that in OTEC the cold exhaust (water very
deep in the ocean) would be about 4º C. Don’t forget to convert temperatures
to Kelvin!
Problems 9. and 10. Kelvin!
"Further Activity" 5 (p 124). DO the experiment at home! In other words,
use a cup or water bottle to catch drips to estimate how much water is wasted
if the faucet dripped for, say one hour. Use this to estimate the energy
wasted by heating this water (calories = grams x change in temp), convert
to kWh. OK to use cold water in the drip experiment of course.
Chapter 5
Problems 1 and 7