Question

Calculate the acceleration of airplane that starts at rest and reaches a speed of 45 m/s in 9 seconds.

Answer 1

`a=(\Delta v)/(\Delta t)=(45\,(\mathrm m)/(\mathrm s)-0\,(\mathrm m)/(\mathrm s))/(9\,\mathrm s-0\,\mathrm s)=(45\,(\mathrm m)/(\mathrm s))/(9\,\mathrm s)=5\,(\mathrm m)/(\mathrm s^2)`

Note that this is the average accelaration over these 9 seconds.