Question

Define\[1kgf\]. How it is related to S.I. unit of force?

Answer 1

Hint: We should know the full form of \[kgf\] first. It is known as kilogram-force. It is a unit of force but not a S.I. unit. But it is closely related to S.I. unit of force \[N\]. It is a gravitational metric unit of force.

Complete solution: Here we are discussing kilogram-force or\[kgf\]. The definition for \[1kgf\] is given as \[1kgf\] is equal to the magnitude of force exerted on a unit mass (i.e., \[1kg\]). In a nutshell, \[1kgf\] is the weight of a kilogram under standard gravity.
Now, we can numerically find the value of \[1kgf\] by multiplying \[1kg\] with acceleration due to gravity\[g\].
         \[\Rightarrow 1kgf=1kg\times g\]
        \[1kgf=1kg\times 9.8m/s=9.8N\]
From this we can easily understand the relationship between \[1kgf\] and S.I. unit of force which is \[N\].
         \[1kgf=9.8N\]
          Or \[1N=\dfrac{1}{9.8}kgf=0.102kgf\]
In addition to this, Kilo-gram force is used as the standard unit of Vickers hardness test which is a method used to measure hardness of materials. The unit decanewton (\[daN\]) which is exactly \[10N\], is used in some fields as an approximation to the kilo-gram force, because it is close to \[9.8066N\]of\[1kgf\].
  The unit kilo-gram force is nowadays used for measuring tension of spokes in bicycles, for informal references to pressure such as\[1kp/c{{m}^{2}}\] which is known as technical atmosphere (\[at\]) which is close to \[1bar\]and\[1atm\].

 Note: Kilogram-force is a non-standard unit of force and is unacceptable with S.I. It is usually made to make the calculation easier as it is \[\approx 10\times 1N\]. The definition of \[1kgf\] is as above mentioned.