21
When Collected Wisdom takes its 1978 AMC Gremlin out on the highway, we always keep a check on what sort of mileage we're getting. That is, if the thing manages to travel more than a mile — sorry, 1.609344 kilometres.
THE QUESTION: "In the seventies when gasoline was in short supply, the speed limit on highways was reduced to 55 miles an hour because that was the most efficient cruising speed," writes Sudhir Jain of Calgary. "What is the most efficient cruising speed for modern cars?"
THE ANSWER: It's all about transmissions, writes Aaron McDonnell of London, Ont.
In the early 1970s, he says, most vehicles used three-speed automatic transmissions with manuals having four speeds. Forty-five to 55 miles an hour (72 to 88 kilometres an hour) was around the point where the top gear in the transmission was making engine combustion as efficient as possible.
Related Articles
"In modern cars, four-, five- and even six-speed transmissions are more common," he says, and the gear ratios are designed to make engines stay at their most efficient. "But even today, the target speed for efficiency isn't much higher — 55 to 65 mph (88 to 104 km/h)."
Peter Blair of Garibaldi Highlands, B.C., adds: "When the U.S. government lowered the speed limit to 55 mph, the mortalities from road accidents dropped dramatically. I do not know the most efficient speed for vehicles today but for saving lives, slower is better."
THE QUESTION: Why do bulls charge the colour red in the bull ring? asks Yves Joly of Richmond Hill, Ont.
THE ANSWER: "The simple answer is, because it's there," writes Cathrine Lowther of Belgrade, Serbia.
"Bulls are colour blind. After being tormented by two picadors who stab the bull's hump with lances, and three banderilleros, who further torture it by stabbing it with sharp metal poles (all left in the bull for maximum pain and aggravation), the bull will attack just about anything that moves in front of it.
"Tradition has it that the matador's little cape is red to hide any of the bull's blood that gets on it, but that may just be an ex post facto explanation -- at this point there is usually blood all over the sand of the arena. In fact, by the time the matador is ready to do his fancy dance, the bull is usually dying from loss of blood."
HELP WANTED
On Wednesday, Erin Orsztynowicz of Collingwood, Ont., bought a basketful of Ontario peaches from his local grocery store. But by Thursday afternoon, when he picked one up for a snack, there was an explosion of fruit flies. His question: How does a grocery store not have fruit flies raiding its produce?
Jackie Phillips of Toronto writes: "You're driving your car at 100 kilometres an hour. You switch on the headlights. Is the light from your headlights now travelling 100 km/h faster than the speed of light?"
"Why do tornadoes seem to touch down only during daylight hours?" writes Vils M. DiSanto of Richmond Hill, Ont. "Is there a scientific explanation for this perception of mine?"
"A 60-storey building with a very large crane on top is under the final stages of construction," writes Iain Mackie of Vancouver. "How does the crane rise as the building goes up and how do they get the crane down once the building is complete?"
Send answers (and questions) to wisdom@globeandmail.com. Include your name, location and a daytime phone number.
