Question

Calculate the force required to lift a load of $60\,N$, placed at a distance of $3\,m$, from the fulcrum. The effort force is applied at a distance of $6\,cm$ from the fulcrum.

Answer 1

The Principle of Moments, commonly known as Varignon's Theorem, asserts that every force's moment is equal to the algebraic sum of the moments of its components. It's a crucial principle that's frequently used in conjunction with the Principle of Transmissibility to solve systems of forces operating on and/or within a structure. This notion is utilised to address the problem in this case.

Formula used:
Moment = force F $\times$ perpendicular distance from the pivot d.
Moment = F $\times$ d

Complete step by step answer:
In physics, a force is any influence that, when unopposed, causes an object to change its velocity. A force can cause a mass item to change its velocity (which includes starting to move from a standstill), i.e. accelerate. Intuitively, force may be characterised as a push or a pull. A force is a vector quantity since it has both magnitude and direction. The SI unit of Newton is used to measure it (N). The letter $F$ is used to signify force.

In physics, a moment is an expression that accounts for how a physical quantity is situated or organised by combining the product of a distance and a physical quantity. When a body is balanced, the total clockwise moment at a point equals the total anticlockwise moment around the same point, according to the Principle of Moments. Moments are generally described in terms of a specific reference point, and they deal with physical values that are at a certain distance from that point.

A moment may be created by multiplying any physical quantity by a distance. Forces, masses, and electric charge distributions are all often used quantities.
${{\text{F}}_1} = 60\;{\text{N}},{{\text{l}}_1} = 3\;{\text{m}},{{\text{l}}_2} = 6\;{\text{cm}},\;{{\text{F}}_2} = ?$
Moment on the left side, near the fulcrum $= 60 \times 3 = 180{\text{Nm}}$
Moment on the right side, near the fulcrum $= 6 \times {10^{ - 2}} \times {\text{x Nm}}$
According to principle of moment, L.H.M = RHM
$180 = 6 \times {10^{ - 2}} \times x$
${\text{x}} = \dfrac{{180}}{{6 \times {{10}^{ - 2}}}} = 3000\;{\text{N}}$
$\therefore x = 3000\,N$

Hence, a force of 3000 N is required to lift the load.

Note: Do not get confused with moment and momentum as these are two different terminologies. In physics, a moment is an expression that accounts for how a physical quantity is situated or organised by combining the product of a distance and a physical quantity.