[Piwoslaw]

Originally Posted by Piwoslaw

We also made two quizzes, one was about the public transport system (How many subway stations in Warsaw?, How many bus lines?, How much more space does it take to carry X people in cars than in a bus?, etc.), the other about ecodriving. If I find a minute, I'll translate and post it for others to use. (If I don't post it within a month, then someone please bug me about it.)

And here it is:

1. By how much does air drag increase when after accelerating from 50 km/h to 70 km/h?
   a) 20%
   b) 50%
   c) 100%
   d) 200%
   
   Answer: c) 100%. Drag increases with the square of speed, so a 40% increase in speed doubles the air resistance, while going twice as fast - increases drag fourfold.
   
2. Which braking method uses less fuel?
   a) Accelerating until the last moment, then sudden hard braking.
   b) Coasting in neutral, then lightly braking.
   c) Engine braking (gear reduction if necessary).
   
   Answer: c) Engine braking. Engines with fuel injection cut off fuel when engine braking, allowing the car to travel a certain distance "for free". Coasting in neutral still requires fuel to keep the engine idling.
   
3. An underinflated tire has less rolling resistance than a well inflated tire.
   a) True
   b) False
   
   Answer: b) False. Higher pressure = Lower RR.
   
4. An underinflated tire has less grip than a well inflated tire.
   a) True
   b) False
   
   Answer: a) True. In spite of what most people believe, research has shown that underinflated tires give a longer braking distance, reducing safety.
   
5. Which acceleration method uses less fuel?
   a) Slowly building up speed.
   b) Quick acceleration with upshifting as soon as possible.
   c) Quick acceleration with high rpms.
   
   Answer: b) Quick acceleration with upshifting as soon as possible. You should get up to speed as quickly as possible, but without exceeding 2000 rpm (diesel) or 2500 rpm (petrol). Throttle should be at about 75%-80%.
   
6. How much fuel does an engine consume when idling?
   a) Idling doesn't consume fuel.
   b) About 0.1 liter per hour.
   c) From 0.5 to 1 liter per hour.
   
   Answer: c) From 0.5 to 1 liter per hour. This depends on the size and type of engine, and on accessories that put a load on the engine (lights, wipers, radio, heated seats, window defogger, etc.).
   
7. After starting a cold engine:
   a) You should wait 5-10 minutes until the engine warms up.
   b) You should immediately start driving, but without "flooring it".
   c) You should immediately start driving, putting a load on it to help it warm up faster.
   
   Answer: b) You should immediately start driving, but without "flooring it". An idling engine takes longer to warm up, so parts are moving without proper lubrication for a longer time. Hard acceleration at high rpms also causes accelerated wearing of parts.
   
8. Driving with a roof rack increases fuel consumption by:
   a) Up to 10%
   b) Up to 20%
   c) Up to 30%
   d) Over 30%
   
   Answer: d) Over 30%. Even an empty roof rack or roof rails can increase fc by as much as 5%-15%.
   
9. Below what speed does air drag stop effecting fuel consumption?
   a) 100 km/h
   b) 70 km/h
   c) 50 km/h
   d) 30 km/h
   
   Answer: None of the above This is a trick question. Air drag causes resistance at any speed, as anyone who tries to ride a bike at 40-50 km/h for a longer time will find out.