Curioustab Logo Curioustab
Home » Civil Engineering » SI Units

Gravitational unit check: select the S.I. force equivalent of one kilogram-weight (1 kgf).

Difficulty: Easy

Correct Answer: 9.8 N in S.I. system

Explanation:


Introduction / Context:
Kilogram-weight (kgf) is a gravitational (non-S.I.) unit of force historically used in engineering. Converting kgf to newtons is essential when reconciling legacy specifications with modern S.I. calculations in design and testing.


Given Data / Assumptions:

  • Standard gravity g0 ≈ 9.80665 m/s^2.
  • 1 kgf is defined as the weight of 1 kg under g0, so 1 kgf = 9.80665 N.
  • Rounded engineering value often used is 9.8 N.


Concept / Approach:
Apply the definition of weight: W = m * g. For m = 1 kg at standard gravity, W = 9.80665 N. In many problems, 9.8 N is accepted given typical significant-figure constraints.


Step-by-Step Solution:

Define: 1 kgf = weight of 1 kg under g0.Compute: W = 1 * 9.80665 ≈ 9.80665 N.Round appropriately → 9.8 N.


Verification / Alternative check:

Cross-check reciprocal: 1 N ≈ 0.10197 kgf; multiply 9.80665 N by 0.10197 kgf/N ≈ 1 kgf.


Why Other Options Are Wrong:

8.9, 4.5, 5.4 N: numerically inconsistent with g0; too small.10.0 N: a rough round-up beyond standard 9.81; not the accepted value for 1 kgf.


Common Pitfalls:

Confusing kilogram (mass) with kilogram-force (force).Using g = 10 m/s^2 for convenience without noting the approximation error.


Final Answer:

9.8 N in S.I. system
← Previous Question Next Question→

More Questions from SI Units

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion