# Q. How far does your car,moving at 70 mi/hr=(112 km/h) travel forward during the 1 s of time that you have to look at an accident on the side of road?

tjbrewer | Certified Educator

Since our time is measured in seconds, we have to convert speed from miles per hour to miles per second.  There are 60 minutes in one hour and 60 seconds in one minute.  So there are `60^2` seconds in one hour or 3600.  `(70 mi)/(1 hr) xx (1hr)/(3600s)`We cancel the hours and we are left with ` ``7/360 mps` This is of course an unsuitable measurement for such a short distance so we switch to the metric

Applying the same conversion to km/s we get `(112 km)/(1 hr) xx (1 hr)/(3600 s)=112/3600` km/s, and then we convert km to meters.  ` ` `(112 km)/(3600 s) xx (1000 m)/(1 km)=1120/36=31 1/9` m/s.

So in the one second you glance at the accident you travel `31 1/9` meters.

justaguide | Certified Educator

The speed of the car is 70 mi/h or 112 km/h. The speed in m/s is `112*(1000/3600)` = 31.11 m/s

The distance traveled by the car in 1 second is 31.11 m