What is the SI unit of Force?

Appeared in: RRB Nsg. Superintendent-20 July 2019 (Shift-2)

Explanation

Newton (N) is the designated International System of Units (SI) for the physical quantity of force.
It is a derived unit, defined as the force necessary to provide a mass of one kilogram with an acceleration of one meter per second squared (1 N = 1 kg·m/s²).
The unit is named in honor of Sir Isaac Newton due to his significant contributions to classical mechanics and the laws of motion.

Option A: Dioptre is the unit of measurement for the optical power of a lens or a curved mirror, not force.
Option C: Hertz (Hz) is the SI unit of frequency, representing cycles per second.
Option D: Decibel (dB) is a logarithmic unit used to quantify sound level or power ratios, not a direct measure of force.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain SI unit of Force as background academic context rather than a clinical decision trigger.
Understanding the concept of force is crucial in biomechanics, for example, when assessing the forces exerted on a patient's joints during lifting and transferring to prevent injury.
The concept of pressure (Force per unit Area) is fundamental in nursing for the prevention of pressure injuries (bedsores), which are caused by sustained force on the skin and underlying tissues, compromising blood flow.
What if? If the question asked for the unit of force in the older CGS (Centimetre-Gram-Second) system, the correct answer would be the 'dyne'.

How to Approach the Question

Step 1: Identify the key terms in the question, which are 'SI unit' and 'Force'.
Step 2: Recognize this as a direct recall question based on fundamental physics principles often covered in general science sections of nursing exams.
Step 3: Mentally review the definitions of the options. Associate 'Newton' with force, stemming from Newton's Laws of Motion.
Step 4: Systematically eliminate the other options by recalling their specific applications: Dioptre for lenses/vision, Hertz for frequency, and Decibel for sound level.
Step 5: Conclude that 'Newton' is the only unit directly related to the physical quantity of force.

Concept Tested & Keywords

QfVRrFshydaqb06cpzuBiD

E6 Psychology Morgan King 9e Part 1 pp. 115-117, 146-148

Practise the full RRB Nsg. Superintendent-20 July 2019 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.