Question

A reconnaissance plane flies 556 km away from

its base at 832 m/s, then flies back to its base
at 1248 m/s.
What is its average speed?
Answer in units of m/s

Answer 1

We use the formula, to calculate the average speed of the round trip,

`v_(av) =(d_(total))/(t_(total))`

Here,
`d_(total)`, is total distance covered by plane in total time,
`t_(total)`.

For the round trip,

`d_{total=556\ km+556\ km=1112 * 10^3\ m`

`t_(total)=(556 * 10^3 m)/(832 m/s) + (556 * 10^3 m)/(1248 m/s)`.

Thus,

`v_(av) =(1112 * 10^3\ m)/((556 * 10^3 m)/(832 m/s) + (556 * 10^3 m)/(1248 m/s)) =(1112 * 10^3\ m)/(668.26\ s+445.51\s) \\\\v_(av)=998.41\ m/s`.