Context and question: St. John's has a humid continental climate (Koppen Dfb), with lower seasonal variation than normal for the latitude, which is due to Gulf Stream moderation. However, despite this maritime moderation, average January high temperatures are actually slightly colder in St. John's than it is in Kelowna, British Columbia, which is an inland city that is near the more marine air of the Pacific, demonstrating the cold nature of Eastern Canada. Mean temperatures range from 4.9 C (23.2 F) in February to 16.1 C (61.0 F) in August, showing somewhat of a seasonal lag in the climate. The city is also one of the areas of the country most prone to tropical cyclone activity, as it is bordered by the Atlantic Ocean to the east, where tropical storms (and sometimes hurricanes) travel from the United States. The city is one of the rainiest in Canada outside of coastal British Columbia. This is partly due to its propensity for tropical storm activity as well as moist, Atlantic air frequently blowing ashore and creating precipitation.
From where do tropical storms travel from to St. John's?
Answer: United States
Context and question: London has a diverse range of peoples and cultures, and more than 300 languages are spoken within Greater London. The Office for National Statistics estimated its mid-2014 population to be 8,538,689, the largest of any municipality in the European Union, and accounting for 12.5 percent of the UK population. London's urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants according to the 2011 census. The city's metropolitan area is one of the most populous in Europe with 13,879,757 inhabitants,[note 4] while the Greater London Authority states the population of the city-region (covering a large part of the south east) as 22.7 million. London was the world's most populous city from around 1831 to 1925.
What is the population of metropolitan London?
Answer: 13,879,757
Context and question: Large brushes are desired for a larger brush contact area to maximize motor output, but small brushes are desired for low mass to maximize the speed at which the motor can run without the brushes excessively bouncing and sparking. (Small brushes are also desirable for lower cost.) Stiffer brush springs can also be used to make brushes of a given mass work at a higher speed, but at the cost of greater friction losses (lower efficiency) and accelerated brush and commutator wear. Therefore, DC motor brush design entails a trade-off between output power, speed, and efficiency/wear.
Besides wear, what is a downside of stiff brush springs?
Answer:
lower efficiency