why is it when you travel 60 miles per hour in a car but u never travel the distance in one hour why have mph?

Answer 1

Actually, you DO travel one hour in a car if you travel 60 mph. The problem is that you DON'T travel that fast consistently. You hit hills, curves, stops; slow down when someone is in front of you, etc. etc. You might get tired and let off on the gas for a moment. Your car's cruise control will have to adjust when you hit a steep hill. All of this costs you time. Take away all of this, however, if you travel 60 mph consistently, you will, indeed, travel 60 miles in an hour, by definition. Regardless, how long it takes you to get where you want to get has little to do with the "why" question. We "have" mph for a completely different reason: to keep you from going 70 when you are not supposed to.

Answer 2

Its the buildup of inaccurate measurements. When youre speedometer shows 60 youre really going anywhere from 55-65 depending on your car. Neither you nor a cruise control computer can actually hold it right at 60mph, even on a straight line with no elevation-there will always be some shifting up and down in speed. Dont forget to incllude surface changes, elevation changes, turns, and other factors altering your speed slightly.

Its simply impossible to make things 100% accurate.

When you try to make a prediction based on measurements that cant be 100% accurate your prediction will be wrong by at least a small amount--chaos theory at work. The more imprecise measurements and the further out your trying to predict, the more pronounced the variations become.

Answer 3

If everything was a constant,and at brand new the speedo was calibrated exactly right [doubtful] as time goes by tyre wear can change the ammount of revolutions the wheel does per mile.This doesnt need to be by much but over 60 miles it can make one heck of a difference.When tacho,s first became mandatory i used to fit them as plenty of vehicles didnt have them.On the calibration cert i had to record tyres fitted and tread depth as on large tyres it was easy to calibrate and then have the customer change wheels.It makes a big difference on 20,s tyres Stay lucky

Answer 4

It is actually very useful on long journeys on less crowded roads. For example, when I am going on holiday in France I know that I have to travel say 400 miles and if I am averaging 50mph I know it is going to take me 8 hours and if I am averaging 80mph it is going to take me 5 hours. The reality is that it will be somewhere in between. So if after 2 hours I have covered 120 miles and I am averaging 60mph, I start to get an idea of how long my journey is going to take.

Answer 5

But, by definition, 60 miles per hour means that, if you travel at this speed constantly for one hour, you will have covered 60 miles. Therefore, I don't understand what you're getting at.

Answer 6

i think i know what you mean i was travelling in a transit van along the motorway and it said 48 miles to where i was heading i was going at constant 60 to 62 mph so why did it take just over an hour to get to my destination

Answer 7

if your going in a straight line you do travel the distance. but the twists and turns make your travel time a little longer

Answer 8

john's correct, unless your timing it from a zero start, 60mph is just that~ 60 miles as long as there is NO deviation from 60mph

Answer 9

Given the parameters of the problem, it is not possible

Answer 10

Different transmissions feature speedometer cables that are calibrated differently .