Question

An airplane requires for take off a speed of $80km{h}^{-}{}^1$, the run on the ground being $100m$. The mass of the plane is $10,000kg$ and the coefficient of friction between the plane and the ground is $0.2$. Assuming that the plane accelerates uniformly during the take-off, the minimum force required by the engine for take off is:

• A. $2\times {10}^{4}N$
• B. $2.43\times {10}^{4}N$
• C. $4.43\times {10}^{4}N$
• D. $8.86\times {10}^{4}N$

Answer 1

The correct option is C $4.43\times {10}^{4}N$

$v_{final}=v=80\times \frac{5}{18}=\frac{200}{9}㎧s=100m{u}_{initial}=u=0v^2=2as\frac{200\times 200}{81}=2a\times 100a=\frac{200}{81}㎨a=\frac{F}{m}-\frac{\mu mg}{m}\frac{F}{m}-0.2\times 10\frac{F}{m}=\frac{200}{81}+2F=4.43\times {10}^{4}N$