This document provides an overview of concurrent and coplanar force systems. It defines concurrent forces as multiple forces acting at a single point and coplanar forces as multiple forces acting in a single plane. Lami's theorem is introduced which states that for three coplanar forces in equilibrium, each force is proportional to the sine of the angle between the other two forces. Examples are given to demonstrate determining tensions in strings for systems with concurrent and coplanar forces, including strings supporting a lamp, a sphere tied to a wall, and a string passing over pulleys with attached weights.

2.  Introduction
 Equilibrium of Concurrent and Coplanar Force Systems
 Lami’s Theorem
 Free Body Diagram
 Examples

3.  If two or more than two forces are acting on a single point then the
forces are known as system of concurrent forces and if they are acting
on a single plane then the forces are called as coplanar forces.

5. If three coplanar forces simultaneously acting at a point are in equilibrium
then each force is proportional to the sine angle of the other two forces.
Consider the forces A, B and C as shown in figure.
 sinsinsin
CBA


6. Determine the tension in the strings that support a lamp fixture as shown
in figure.

7. A sphere weighing 100 N is tied by a string to a smooth wall as shown in
figure. Determine the string tension in the concurrent and coplanar system
of forces.
195°
90°
R
100N
T
75
15
Space Diagram
15
W
Free Body Diagram
T
100N
R
Fig. 23

8. Determine A string ABCDE whose one end A is fixed to the wall and the
other end E is loaded with a weight of 300N. The string passes through a
frictionless pulley and other two weights are hung at B and C as shown in
figure. Determine the tension in the string and the magnitude of weights
W1 and W2.

9. This was just a summary on Tension for Concurrent and Coplanar Force
System. For more detailed information on this topic, please type the link
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