2006-10-06 11:27:34 · 13 answers · asked by whoknows 1 in Science & Mathematics ➔ Physics
Opening the windows reduces the aerodynamic efficiency of the car.
Put simply, a car is design to slip through the air reducing the air resistence as much as possible. Opening the windows disturbs the "slippery" shape of the car and increases drag (drag is another word for air resistance, basically). This means that the car has to put in more work, and therefore use more fuel to push itself through the air.
Hope this helps
2006-10-06 11:31:02 · answer #1 · answered by Stuart T 3 · 1⤊ 0⤋
With the windows open, the car has a higher drag coefficient so the wind resistance is higher. This consumes more fuel.
Wind resistance increases as the velocity squared. So, the wind resistance increases by a factor of 4 if you increase the speed by a factor of two. So, if you go fast enough, keeping the windows rolled down will consume more energy than keeping them up and turning on the air conditioner.
2006-10-06 11:31:10 · answer #2 · answered by Guru 6 · 0⤊ 0⤋
The car's air resistance is increased, as more drag is created by air becoming 'trapped' within the car and the engine having to put more effort into keeping up the same speed. Imagine it like walking along in a wind tunnel, then opening a big parachute behind you...
Same kind of things happens with bikes or luggage racks on the top of the car.
2006-10-06 11:45:18 · answer #3 · answered by Anonymous · 0⤊ 0⤋
having the windows down changes the way the car displaces the air it is travelling through. If it increases the resistance enough, it will take more power/fuel to maintain the speed that it would use to run the A/C.
2006-10-06 11:31:51 · answer #4 · answered by Anonymous · 0⤊ 0⤋
The open windows generate great turbulence in the air stream passing them, and that takes a lot of energy. Same idea applies to spoilers on the top of airplane wings -- raise the spoiler, and the turbulence creates lots of drag while reducing the lift.
2006-10-06 18:04:11 · answer #5 · answered by Anonymous · 0⤊ 0⤋
by having the windows open your car gets resistance by the wind getting trapped inside the car you might as well roll up the windows and turn on the a c because it makes no differance on fuel consumption
2006-10-06 11:32:46 · answer #6 · answered by Anonymous · 0⤊ 0⤋
Most likely because of aerodynamics. Most automobiles are aerodynamic, but when you leave the windows open, you get somewhat of a parachute effect, and it takes more energy for the car to continue at a certain speed.
2006-10-06 11:31:06 · answer #7 · answered by indian_gogirl 2 · 0⤊ 0⤋
wind resistance caused by air entering the car through the windows. the aerodynamics of the vehicle significantly decrease
2006-10-06 11:35:35 · answer #8 · answered by Jacobus B 2 · 0⤊ 0⤋
Increased air resistance with windows open, increased drag coefficient due to formation of vortices.
2006-10-06 11:39:44 · answer #9 · answered by Kainoa 5 · 0⤊ 0⤋
Drag (air resistence) is proportional to (speed)^2.
2006-10-06 11:59:03 · answer #10 · answered by entropy 3 · 0⤊ 0⤋