Answer:
The f-ratio describes the relationship between the lens diameter and the focal length and is calculated by dividing the focal length by the diameter of the lens. For example, if a lens were to have a focal length of 50mm and a diameter of 10mm, then the f-ratio would be 50mm/10mm=5 or otherwise referred to as f5.
Explanation:
Answer: 1
Explanation:
Given
Tension is the string 
mass of object 
Tension is greater than the weight of the object i.e. elevator is moving upward
we can write

As shown in the figure, the ideal mechanical advantage is calculated by dividing the radius of the wheel by the radius of the axle. Any crank-operated device is an example of a wheel and axle. Force applied to a wheel exerts a force on its axle.