Question

The speed limit on some interstate highways is roughly 80 km/h. What is this in meters per second? How many miles per hour is this?

Answer 1

Answer:

1) Speed in m/s equals 22.22 m/s.

2) Speed in miles per hour equals 49.712 mph.

Explanation:

Since we know that in 1 kilometer there are 1000 meters and in 1 hour there are 3600 seconds hence we can write

$80km/h=\frac{80\times 1000m}{3600s}=22.22m/s$

Now we know that 1 mile equals 1.609 kilometer  hence we conclude that 1 kilometer equals $\frac{1}{1.609}=0.6214$mile

Hence

$80km/h=\frac{80\times 0.6214miles}{1h}=49.712mph$