Question

An aeroplane of mass 30000kg produced a force of 20kN to get it to accelerate to 50m/s so it could take off. Calculate the amount of time it was accelerating for


Will mark branliest! Need working out aswell!

Answer 1

Answer:

$75\:\mathrm{seconds}$

Explanation:

The impulse-momentum theorem states that the impulse of an object is equal to the change in momentum of that object:

$\Delta p=m\Delta v$.

Impulse is also given by $F\Delta t$ where $F$ is the average net force and $\Delta t$ is change in time.

Therefore, we can set both equations equal to each other and solve:

$\Delta p= F\Delta t$.

Assuming that the airplane was initially at rest, its change in momentum is:

$\Delta p =m\Delta v,\\\Delta p=30,000\cdot 50=1,500,000$

Impulse is represented using $Ns$. Therefore, convert $20\:\mathrm{kN}$ to Newtons:

$20\:\mathrm{kN}=20,000\:\mathrm{N}$

Thus:

$1,500,000=20,000\cdot t,\\t=\frac{1,500,000}{20,000}=\fbox{ 75\mathrm{s} }$.