LEBANON COLLEGE - Lebanon, NH

SCI 180 - PHYSICS - Homework Assignment

1. Weigh yourself using your favorite scale and write down your weight.
2. Calculate your mass in kilograms (kg).
3. Calculate your weight in Newtons (N).
4. Calculate your mass in slugs.
5. Write down your height in inches (recall there are 12 inches to a foot).
6. Calculate your height in meters (m).
7. Calculate your height in kilometers (km).
8. Estimate your volume:  First measure the length of your forearm (elbow to wrist) and express it in meters.
9. Now take your volume to be your height times the square of the length of your forearm.  What is it?
11. Your "specific gravity" is your density divided by the density of water, which is 1000 kg/m3.  Write it down.
12. According to the Coca-Cola Company, a 240-milliliter (mL) serving of caffeine-free Coca-Cola Classic stores 100 Calories of energy.  How many J is this?  (Recall that 1 Calorie is 1000 calories and one calorie is 4.186 J.)
13. If you drink a 240-mL glass of Coke in one minute, what is the average power delivered to your body?
14. How many times would you have to lift the glass of Coke from the floor to the top of your head to "wear out" the energy it contains before you imbibe it?  (Assume you just drop it before you lift it again.  Take the density of Coke to be the same as that of water; a liter of water has mass 1 kg.  Also neglect the mass of the container.)
15. According to National Grid, one kilowatt-hour (kWh) of electric energy costs 13.04 cents (if you use up to 250 kWh a month; the price increases if you go beyond that).  How many megajoules (MJ) are there in a kWh?
16. How much does a joule of electricity cost?
17. How much does it cost to have a 60-W light bulb turned on for a whole 30-day month?
18. One 42-gallon barrel of West Texas Intermediate (WTI) petroleum cost \$136.91 on June 12th (US DOE Energy Information Agency).  WTI has a specific gravity of about 0.827  (Wikipedia).  What is the mass of 42 gallons of WTI?  (For a quick conversion go to Google and type "42 gallons in cubic m".)
19. How much does a kg of WTI cost?
20. One barrel of WTI stores 6119.32 MJ of energy (US DOE Energy Information Agency).  How much does a joule of petroleum energy cost?
21. To what height above the surface of the Earth would you have to lift a barrel of oil if you want to double the energy you are storing in it?  Express it in terms of the Earth's radius.
22. At what speed would a barrel of oil have to be moving if it is to store double the energy it stores when standing still?
23. How many calories are there in a 240-mL glass of WTI?
24. The masses of cars vary from about 103 kg to 2 x 103 kg.  Look up the mass of a 2001 Honda Civic and write it down (websites will refer to the weight of the car, but they are really giving the mass).
25. How much energy do you need to start that car and get it to move at 55 mph?