 # Normal Force Formula

Normal Force

The normal force is a force of contact. When two surfaces are not in connection, a normal force can not be exerted on one another. For example, consider a table and a container, when they are not in contact not possible to exert normal force on one another. But, when two objects are touching one another, they exert normal force on one another vertical to the contacting surface. Here normal denotes to perpendicular.

The normal force is equal to the weight of the body during deceleration. When the body is about fall, depends on the location of the body on the ground. The normal force is represented by Fand measured in terms of N (Newtons)

An object during rest on the flat surface the normal force FN is

FN = mg

Where,

g = Gravitational Force
m = mass is m

A force acting on a falling object it drops at an angle of θ, then the FN is grater than the formulated weight,

FN = mg + F sin θ

Where,
the normal force is FN
the mass of the body is m
gravitational force is g
the angle with which body falls is θ

A force tugs the object towards upward,  then FN is less than its weight

FN = mg – F sin θ

Where,
the normal force is FN
the mass of the body is m
gravitational force is g
the angle with which body moves up is θ

An object placed on an inclined plane then normal force FN is

FN = mg cos θ

Where,
the normal force is FN
the mass of the body is m
gravitational force is g

The angle of the inclined surface is θ

Solved Example

Example 1: A text-book of mass 1.7 kg is kept on the table. Calculate the normal force being applied on the book.

Solution:

Given:

m  = 1.7 kg

w.k.t g (gravitational force) = 9.8 ms-2

The normal force is

FN = mg

FN = 1.7 × 9.8

FN = 16.66 N

Thus, the normal force being applied on the textbook is 16.66 N.

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