Question

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A long wooden post is suspended horizontally by a rope attached to the ceiling at distance

Δx = 1.20 m

from the end. A pylon supports the other end as shown below. The 4.80 m long post is uniform along its length and has a mass of 34.5-kg. A 10.0-kg mass is suspended at a distance

Δx = 1.20 m

from the other end.

(a) Find the tension in the rope.
  N

(b) Find the force that the pylon exerts on the end of the post.
  N

Answer 1

From draw the diagram wortg 2.4m The weight of the post that acts at the middle at point O is, W = mg = (34.5)(9.8) = 338.1 N The weight of the mass is, Wi = m 8 = (10)(9.8) = 98 N (a) Let ‘T' be the tension in the rope For rotational equilibrium, EM, = 0 -T(3.6)+W(2.4)+W (1.2)=0 W (2.4)+W (1.2) T= 3.6 (338.1)(2.4)+(98)(1.2) 3.6 = 258 N (b) The vertical equilibrium is, EF, = = 0 T+R, -W -W, = 0 R, =W+W, -T = 338.1+98-258 = 178 N