"Q 12.10: A 98 N object is placed 1/3 of the way up a 120 N ladder, which makes an angle of 53 degrees with the horizontal. The lower end is also fastened to the wall by a rope, and both the wall and floor are frictionless. What is the tension in the rope?"

Respuesta :

Answer:

68.829 N

Explanation:

The given parameters are:

Weight of ladder, [tex]W_l[/tex] = 120 N

Weight of object, [tex]W_o[/tex] = 98 N

Angle, [tex]\theta[/tex] = 53°

And we also know that, while

Length of ladder = L

Distance the object is placed = L/3

If we apply translational equilibrium horizontally, then [tex]T-N=0[/tex], so [tex]T = N[/tex]

If we apply rotational equilibrium about the distance the object is placed, then

[tex]W_o\frac{L}{3}cos(\theta) + W_l\frac{L}{2}cos(\theta) - NLsin(\theta) = 0\\2NLsin(\theta) = 2W_o\frac{L}{3}cos(\theta)+W_lLcos(\theta)\\2Tsin(\theta) = \frac{2}{3}W_ocos(\theta)+W_lLcos(\theta)\\T = \frac{1}{3}W_ocot(\theta) + \frac{1}{2}W_lcot(\theta)\\T = \frac{1}{3} * 98 * cot(53) + \frac{1}{2} * 120 * cot(53) = 69.829[/tex]