The power of sunlight reaching each square meter of the Earth’s surface on a cle
ID: 1404941 • Letter: T
Question
The power of sunlight reaching each square meter of the Earth’s surface on a clear day in the tropics is close to 1000 W. On a winter day in Manitoba, the power concentration of sunlight can be 100 W/m2. Many human activities are described by a power per unit area on the order of 102 W/m2 or less. Con- sider a car 2.10 m wide and 4.90 m long traveling at 55.0 mi/h using gasoline having “heat of combustion” 44.0 MJ/kg with fuel economy 25.0 mi/gal. One gallon of gasoline has a mass of 2.54 kg. Find the power per unit area used by the car.
Explanation / Answer
distance travelled by car in one hour, d = 55 mi
volume of the fuel consumed = 55/25
= 2.2 galons
mass of the fule consumed, m = 2.2*2.54
= 5.588 kg
Energy produced through combustion, E = 44*10^6*5.588
= 2.46*10^8 J
power of the car = Energy/time
= 2.46*10^8/(60*60)
= 6.83*10^4 Watts
power per unit area = power/Area of the car
= 6.83*10^4/(2.1*4.9)
= 6637.5 W/m^2 <<<<<<<<<<-------------------ANswer
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.