Environmental Data Analysis EESC BC 3017

Homework 1 - Answer key

Excel, unit conversions, and significant digits

1.) (6p) Load the file 'park.xls' from the software package, add your name/date on the sheet and print it so that it looks like this.

2.)  (6p) A particularly fine variety of cheese is sold for $1.47 per ounce. What is this price in Euros per kilogram? For exchange rates see website. Please state your calculation steps clearly so that I can follow what you did.

Unit conversion from $/ounce to Euro/kg:
1.47$/oz  = 1.47$/oz *  1 Euro/1.39$ * 1oz/28.3495g * 1000g/kg = 37.3 Euro/kg

3.)  (8p) A rectangular region of forest measuring 5.6 mi by 9.2 mi was destroyed by fire. The forest had a tree density of 1.0 tree per 10 square feet, each tree weighed on average 500 pounds. How many metric tons of wood were destroyed?

The area of the burned forest is A = 5.6*9.2 mi2 = 51.52 mi2 * 1.60932 km2/mi2 * 10002m2/km2 * 1 ft2/0.30482m2 = 1.44*109ft2
The number of trees is then: N = 1.44*109ft2 * 1 trees/10 ft2 = 1.44*108
Consenquently the mass of the forest is: m = 500lbs/tree * 1.44*108 * 0.4535924 kg/lbs * 1 ton/1000kg = 3.3*107 toms

4.) (6p) This summer I have been driving with my new car from NYC to LA and back. I drove 17,000 km and my car consumes 42.5 miles/gal (Diesel). How does the total amount of fuel compare to that if my family and I had flown this distance? There are 4 of us. Find out what a typical plane consumes and perform a back-of-the-envelope calculation.

The mieleage of my car (42.5 miles/gal) can be converted into liters per km:
1/42.5miles/gal = 0.023529 gal/mile * 3.7854 l/gal * 1/1.6093 mile/km = 0.05535 L/km
The total amount of diesel fuel used on teh trip was: 17000 km * 0.05535 L/km = 940 L (almost one ton of diesel!)

For estimating the fuel consumption of an airplane, I used the specification page for a Boing 747-200. The range of the airplane is 12700km, fuel capacity 199158 L and it can transport 366 people. The fuel consumption per person is therefore: 199158 L / 12700km / 366 p = 0.0428 L/km/p.

Consequently teh fuel consumption for 4 people and the 17000 km distance is: 0.0428 L/km/p * 17000 km * 4 = 2900 L, or 3 times that consumed in my car.

5.) (0p) If you had trouble doing the unit conversion calculations in class, please do them at home for yourself. If you continue having difficulties with them, talk to me after class on Tuesday.