posted by Becca on .
The problem I'm trying to answer is:
Ann is driving down a street at 59 km/h.
Suddenly a child runs into the street.
If it takes Ann 0.719 s to react and apply
the brakes, how far will she have moved before
she begins to slow down?
Answer in units of m.
I know the first step is to convert 59 km/h to m/s, but I'm not sure how. I know how to solve the problem after ward. Can someone show me and explain the formula I would need to use for this problem? Thank you!
To convert units, just remember that multiplying by one does not change anything. You just have to pick the way of writing 1 that gets you what you want. You do this all the time, without consciously following the logic. In this case, we have
59km/h * 1000m/km * h/3600s = 16.39m/s
Now, to convert this to meters, just multiply by seconds, so they disappear form the fraction:
1.39m/s * 0.719s = 11.784m