Question

The posted speed limit on the road heading from your house to school is 45 mi/h which is about 20 m/s if you live 8 km from school how long will it take you to get to school if there’s no traffic convert your answer in to minutes

Answer 1

t = 6.7 min.

Step-by-step explanation:

• Assuming there's no traffic, and neglecting the time needed to start from rest, and the one needed to stop, all the path is covered at the same constant speed of 20 m/s.
• Applying the definition of average velocity, taking as the origin your house , you get the time used for the travel from the following expression:

`t = (d)/(v_(avg) ) = (8000 m)/(20 m/s) = 400 s`

• In order to convert the answer to minutes, we need to do the following, multiplying by something equal to one, as follows:

`400 s * (1 min)/(60 s) = 6.7 min.`