MPH – what does it really mean?

It strikes me as being a little odd that speed is usually referred to in miles per hour. Why? well everything that we do has perspective, but I am unsure as to how much perspective we have over the space of an hour.

By way of contextualisation, an hour is a very short period of time, if we refer it to learning, waiting for a parcel, or even learning the Highway Code off by heart! But, if we refer to other examples, i.e. holding our breathe, waiting at red traffic lights or how much distance we cover, then this becomes somewhat a long and harrowing moment of time.

Lets get back to speed – what do we really want to know? – just how quick is it? how much motion or pace do we have?  

Well.. if we go for a little a trip to the moon in our “RoSPA” Rocket, we will need to achieve a speed of 4.9 miles per second to achieve orbital velocity. Again – I can’t really comprehend what that means! But if we do some calculations – we discover that this is 17,640mph! That is 252 times faster than we can go on the motorway. Lets change that now to feet per second, and we will be covering around 25,872 feet per second, otherwise referred to as “fast” 

A foot is roughly the length of a ruler, the portrait length of an A4 piece of paper, or the length of a well known sandwich brands sub-sandwich offering. Its visual. If you prefer to be a little more up to date, times it by 3 and a bit and you’ll be close to a metre. Lets face it, you’ll be closer to working out what a metre is, than you will a mile!

We can easily translate mph in to feet per second. Simply add a half.

i.e. 30 mph + Add half of 30 (15) = 45 feet per second

40mph + 20 = 60 feet per second

50mph + 25 = 75 feet per second

60mph + 30 = 90 feet per second

70mph + 35 = 105 feet per second

Feet per second can really help put perspective in to our driving plan whilst dealing with hazards and ensuring that we can stop in the distance seen to be clear. It has a clear rational perspective and easy to calculate – try it, it might just help!