Question

Define 1 newton.

Answer 1

1 Newton is the S.I. unit of force. So, firstly define the basic definition of what force is and write down its formula in terms of mass and acceleration. Now, describe mass and acceleration in terms of units of the basic physical quantities in order to obtain 1 newton. The basic units of 1 newton is equivalent to ${kg.m}/{{s}^{2}}$.

Complete solution:
Newton which is denoted by N, is a unit of force. The S.I. unit Newton is named after Sir Issac Newton. 1 newton is defined as the amount of force required to accelerate one kilogram of mass at the rate of one meter per second squared in the direction of applied force. Here, meter per second squared can be understood as velocity per second.
Force can be defined as the rate of change of momentum. According to Newton’s second law of motion, the force exerted by an object is directly proportional to the acceleration of that object. We can write this mathematically as,
$F= ma$ …(1)
Where,
$m$ is the mass of the object
$a$ is the acceleration of the object
We know, S.I. unit of mass is kg and that of acceleration is ${m}/{{s}^{2}}$. Also, the S.I. unit of force is 1 newton.
Substituting these units in the equation. (1) we get,
$1 N= {kg.m}/{{s}^{2}}$

Note:
There have been a variety of units of forces and conversion factors. The corresponding CGS unit is dyne which is the force required to accelerate one gram of mass by one centimeter per second squared in the direction of applied force. Thus, one newton is equal to 1,00,000 dynes. The corresponding unit in the foot-pound-second (FPS) system is pound-force.