If each of the three rotor helicopter blades is 3.75 mm long and has a mass of 135 kgkg, calculate the moment of inertia of the three rotor blades about the axis of rotation.

Explanation:

The computation of the moment of inertia of the three rotor blades is shown below:

Given that

Three rotor helicopter blades = 3.75 mm long

Mass = 135 kg

Based on the above information

As we know that

Axis at the end is

Now the total moment of inertia is

Hence, the moment of inertia of the three rotor blades is

We simply applied the above formula and the same is to be considered

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.