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Wonders of Physics


Vector Diagram – Parallelogram Method

For Combined Science (Physics), drawing of vector diagram is a must.
In general, two known forces are given and the resultant force of these two forces is to be found using the vector diagram.

There are two methods to draw vector diagram 1) Parallelogram method and 2) Tip-to-tail method. In this post, the parallelogram method is used.

Example 01
Capture 01

Example 02

Capture 02

Example 03

Capture 03

Example 04

Capture 04

Click here to view another post on Closed-Loop Triangle Method (2 forces, 2 unknowns, 1 known)

Click here to view how parallelogram method is applied to various kind of questions

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Resultant force and Vector Diagram

A trolley is acted on by three forces, P, Q and R in magnitude and direction as shown in the figure below. A single force F could balance all three forces. What is the magnitude of F?


Solutions:There are 3 different forces, P, Q and R acting on the trolley.Consider the forces P and R only, as they are acting perpendicular to each other, the resultant force falls exactly on Q. (using the vector diagram method/parallelogram method).The resultant of P and R is Q, plus the existing Q, will give a final resultant force of 2Q acting on the trolley.