In a giant swing, the seat is connected to two cables as shown, one (B) horizontal and the other 40o angle with the vertical (A). The chair swings in a horizontal circle at a speed of 32 revolutions per minute. If the seat weighs 255 N and a person weighing 825-N is sitting in it, find the tension on cable B. (g = 9,8 m / s2)

Respuesta :

Answer:

The tension in the cable B is approximately 8375.227 N

Explanation:

The given parameters are;

The orientation of one cable, B = Horizontal

The orientation of the other cable, A = 40° to the vertical

The horizontal speed with which the chair swings= 32 revolutions per minute

ω = 32×2×π/60 rad /s

The weight of the seat = 255 N

The weight of the person = 825 N

The acceleration due to gravity, g = 9.8 m/s²

Therefore, we have;

The centripetal force [tex]F_c = \left (m_p + m_s \right ) \times l \times \omega ^2[/tex], which gives;

[tex]F_c = \left (\dfrac{825 + 255}{9.8} \right ) \times 7.5 \times \left (\dfrac{32\times 2 \times \pi}{60} \right )^2 \approx 9281.457[/tex]

The weight of the person and the seat W = 825 + 255 = 1080 N = The vertical force component in the system

The vertical component of the cable A = The vertical force component in the system = 1080 N

Let [tex]T_A[/tex] represent the tension in A

The vertical component of the tension = [tex]T_A[/tex] × cos 40° = 1080

[tex]T_A[/tex] = 1080/(cos(40°)) ≈ 1409.84 N

The horizontal component of [tex]T_A[/tex] =

From ∑Fₓ = 0, given that the centripetal force is acting outwards and the tension in cable B and the horizontal component of [tex]T_A[/tex] are acting inwards, we have;

The centripetal force, [tex]F_c[/tex] = The tension in the cable B + The horizontal component of [tex]T_A[/tex]

9281.457 = The tension in the cable B + 906.23

The tension in the cable B = 9281.457 - 906.23 ≈ 8375.227 N.

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