This past weekend I had to drive to Canada to play in a hockey tournament. While i was in Canada we had to drive on the expressway to get to the ice rink and as we were driving I saw a sign that reminded me of physics on the side of the road. The sign was a speed limit sigh and it said 70 km/hr. This reminded me of physics because for us Americans to know how fast to drive we had to do a metric coversion to get 70 km/hr to mph. After doing a metric conversion 70 km/hr turns into about 44 mph. You can learn how to do metric coversions by watching the metric conversions video on APlusPhysics.com.