Homework 5, due wed oct 28, 2009
			ENVR 30: Fall 2009 

Use the conversion factors and energy formula sheet posted on the web site.

1. A 1/2 kg object is thrown at a velocity of 10 m/s.  How much kinetic
energy does it have in Joules?  In Calories? In Btu? In kWh?

2. One metric tonne (1000 kg) of water flows through a small hydroelectric
plant with a drop of 3 meters.  
a.How much potential energy is released assuming 100% efficiency?  
	in Joules? in Calories? in Btu? in kWh?
b. If the electricity generator is 90% efficient, then how much electricity
    if made in kWh.

3. An AAA battery contains about .0017 kWh.  How much is this in Calories?
	In Btu?  Which contains more energy a potato chip or an AAA battery?
	A match or an AAA battery?

4a. A 150 lb person who normally eats 2000 Calories a day, fasts for one week,
on only water.  They keep the same level of physical activity as normal.
How many pounds of fat will they lose?
4b. The same person continues to eat as normal, but runs 3 miles per day.
How many pounds of fat will they now lose?
[Use 1 pound of fat is 3500 Calories and running one mile takes 100 Calories]

5. You leave a 100 Watt light bulb on all the time.  How many kWh are used
in one year?  If electricity costs $0.15 per kWh, how much will this cost?

6. A family of 5 eats about 12000 Calories per day. 
a. How many Btu/day is this?
b. How many Watts?
c. To wash the dishes water is heated by 70 degrees F (from 70 F to 140 F).
      How many pounds of water can be heated with the 12000 Calories?
d. How many gallons of water is this?  (weight of water is on formula sheet)