Illluminance is the measurement of photometric power. That means, illuminance is the rate of photometric flux that is received by a surface per area. It is usually expressed as a unit of W/m^2.
Thus, from the choices, the answer we're looking for is illuminance<span>.</span>
The ration of output work to input work expressed as a percentage is called <u>Efficiency</u>.
Answer:
The angular speed after 6s is
.
Explanation:
The equation

relates the moment of inertia
of a rigid body, and its angular acceleration
, with the force applied
at a distance
from the axis of rotation.
In our case, the force applied is
, at a distance
, to a ring with the moment of inertia of
; therefore, the angular acceleration is



Therefore, the angular speed
which is

after 6 seconds is


Friction force is when you rub 2 things together and they get warm. Motion, on the other hand, is if your walking along the sidewalk - you hardly get warmer -------
Unless it's a colder day outside and you're walking SO you decide to rub your hands together to get warm, but if you were just walking , its motion and only motion - no friction :):)
Cover your cough
Wash your hands
Keep a clean space
Avoid smoking
Stay active
Hope this helps :)