Question

What is the net force on an $900\,\,Kg$ airplane flying with the same velocity $180\,\,Km\,{h^{ - 1}}$ north?
(A) zero.
(B) $180\,\,N$.
(C) $1800\,\,N$.
(D) $9000\,\,N$,
(E) none of the above is within $20\,\,\% $ of the correct answer.

Answer 1

Hint
The acceleration of an object as produced by a net force is directly corresponding to the magnitude of the net force, in the same direction as the net force, and inversely corresponding to the mass of the object is referred to as Newton's second law of motion.
The formula for the net force on the plane is given by Newton’s second law of motion:
$\Rightarrow F = ma$
Where, $F$ denotes the net that is acting on the plane, $m$ denotes the mass of the plane, $a$ denotes the acceleration of the plane.

Complete step by step answer
The given data from the problem are as follows;
The mass of the airplane is, $m = 900\,\,Kg$.
The velocity of the airplane is, $v = 180\,\,Km\,{h^{ - 1}}$.
The formula for the net force on the plane is given by Newton’s second law of motion:
$\Rightarrow F = ma$
Here, the airplane flies with the same velocity, so the acceleration of the plane is zero.
That is;
$\Rightarrow a = \dfrac{{dv}}{{dt}} $
$\Rightarrow a = 0 $
Now substitute the values of mass of the airplane and the acceleration of the airplane in the above formula;
$\Rightarrow F = 900 \times 0 $
$\Rightarrow F = 0 $
Therefore, the net force of the airplane with the same velocity is calculated as $F = 0$.
Hence the option (A) zero is the correct answer.

Note
To have the same velocity, an object must have the same speed in the same direction. Same direction constrains the object to motion in a straight path thus, the same velocity means motion in a straight line at the same speed.