Aforce of 300 n is applied at a point 1.3 m from the axis of rotation, causing a revolving door to accelerate at 309.4 deg/s2. what is the moment of inertia of the door from its axis of rotation?

Moment of inertia,                                                                                  

Explanation:

It is given that,

Force, F = 300 N

Distance from the axis of rotation, r = 1.3 m

Acceleration,

In linear kinematics, torque is given by :

.............(1)

In rotational kinematics, torque is given by :

.........(2)

I is the moment of inertia

From equation (1) and (2) :

So, the moment of inertia of the door from its axis of rotation is . Hence, this is the required solution.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

snell's law

refractve index = sin incidence / sin refraction