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QUESTION 3 ( MARKS]
A 20 kg sign is suspended from a horizontal rod of negligible weight as shown in
Figure 2. The horizontal rod is kept in equilibrium by a wire attached at point X
of the rod.
Find the tension T In the wire supporting the rod.​

QUESTION 3 MARKSA 20 kg sign is suspended from a horizontal rod of negligible weight as shown inFigure 2 The horizontal rod is kept in equilibrium by a wire att class=

Respuesta :

MathPhys

Answer:

392 N

Explanation:

Draw a free body diagram of the rod.  There are four forces acting on the rod:

At the wall, you have horizontal and vertical reaction forces, Rx and Ry.

At the other end of the rod (point X), you have the weight of the sign pointing down, mg.

Also at point X, you have the tension in the wire, T, pulling at an angle θ from the -x axis.

Sum of the moments at the wall:

∑τ = Iα

(T sin θ) L − (mg) L = 0

T sin θ − mg = 0

T = mg / sin θ

Given m = 20 kg and θ = 30.0°:

T = (20 kg) (9.8 m/s²) / (sin 30.0°)

T = 392 N

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