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- Solutions 3

(a) A bumblebee flies with a ground speed of 15.2 m/s. Calculate its speed in km/hr.

Hey guys, so in this question they tell us that the speed of a bumblebee is 15.2 meters per second and we want to convert meters per second to kilometres per hour. So here we're dealing with 2 units that need to converted, so the way we approach this is we do one unit at a time to achieve the correct positioning. So we have 15.2 meters per second. So you could either start with meter or you could either start with seconds. I'm going to start with meters. So we have to convert from meters to kilometres. We're just going from the base unit to the prefix, so it's just a simple conversion. So we have meters to kilometres. The way I placed meters on the bottom is because I want to be able to cancel out meters with meters, so I'm left with kilometres on the top which is what we're looking for. We know 1 goes wherever there's a prefix, kilo is a prefix so one goes here and kilo is 10 to the 3.

So now since we already achieved kilometres, we next need to convert seconds to hours. The way we do this, so we know that 60 seconds is going to be 1 minute. We place seconds on the top because we want to cancel out seconds with seconds and we know that 60 minutes equals 1 hour. Once again, minutes gets placed on the top here because we want to cancel minutes with minutes and what we're left with is hours on the bottom because our units are kilometres per hour. Now that we have the desired units, and everything has been cancelled out, we multiply everything on the top and divide by everything on the bottom and you guys should get 54.72 kilometres per hour. So once again since we're dealing with converting 2 units at the same time, focus on one unit at a time and once you get the desired unit, you can move on to converting the next set of units. See you guys soon.