Question

an electric light fixture weighting 15N hangs from a point C by two strings AB and BC. the string AC is inclined at angle of 60 degree angle to the horizontal and BC at 45 degree angle to the horizontal. determine the forces in the strings AC and BC​

Answer 1

• AC ≈ 10.98 N
• BC ≈ 7.76 N

Step-by-step explanation:

In this geometry, the force in each string is proportional to the cosine of the angle the opposite string makes with the horizontal, and is inversely proportional to the sine of the sum of the angles.

AC = (15 N)cos(45°)/sin(60° +45°) = (15 N)cos(45°)/sin(105°) ≈ 10.98 N

BC = (15 N)cos(60°)/sin(105°) ≈ 7.76 N

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The relation described above derives from the fact that the sum of vertical forces and the sum of horizontal forces are both zero when the system is in equilibrium.