Last question:
An average person expends ~100 kj to walk 1km. How far will the average car travel by the time it expends the same amount of energy (i.e. 100 kJ) as a person who walked 1 km?
Fuel consumption of average car= 8 km L^(-1)
Heat of combustion of gasoline= 50 kJ g^(-1)
Density of gasoline= 0.7g mL^(-1)
1)2km
2)0.02 km
3) 20 km
How would i solve this?
Energy output of the car is 50 kJ/gram.
So you will need 2 grams to equal 100 kJ (that is, 50 kJ/g x ?g = 100 and solve for ?g).
2 grams is what volume.
mass = volume x density
2 g = v x 0.7g/mL
Solve for v. I think something like 2.85 mL but you need to confirm that to get an exact answer. Then you know the fuel consumption is 8 km/L, how far can you go with 2.85 mL?
To solve this question, we need to calculate the amount of fuel consumed by the car and then use that to determine the distance it can travel.
Step 1: Calculate the amount of fuel consumed by the car to expend 100 kJ of energy:
Since the heat of combustion of gasoline is given as 50 kJ/g, we can calculate the amount of fuel required using the formula:
Amount of fuel (in grams) = Energy (in kJ) / Heat of combustion (in kJ/g)
Amount of fuel = 100 kJ / 50 kJ/g = 2 grams
Step 2: Convert the amount of fuel from grams to volume:
Since the density of gasoline is given as 0.7 g/mL, we can calculate the volume of fuel consumed using the formula:
Volume of fuel (in mL) = Amount of fuel (in grams) / Density (in g/mL)
Volume of fuel = 2 grams / 0.7 g/mL = 2.86 mL
Step 3: Calculate the distance the car can travel using the fuel consumption rate:
The fuel consumption rate of the average car is given as 8 km/L. Let's convert the volume of fuel consumed to liters:
Volume of fuel (in L) = Volume of fuel (in mL) / 1000 mL/L
Volume of fuel = 2.86 mL / 1000 mL/L = 0.00286 L
Finally, we can calculate the distance traveled by the car:
Distance (in km) = Volume of fuel (in L) * Fuel consumption rate (in km/L)
Distance = 0.00286 L * 8 km/L = 0.02288 km
The answer is approximately 0.02 km. Therefore, the correct option is 2) 0.02 km.