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A 0.453 kg pendulum bob passes through the lowest part of its path at a speed of 2.58 m/s. What is the tension in the pendulum cable at this point if the pendulum is 75.1 cm long? Submit Answer Tries 0/12 When the pendulum reaches its highest point, what angle does the cable make with the vertical? Submit Answer Tries 0/12 What is the tension in the pendulum cable when the pendulum reaches its highest point?

Respuesta :

Answer with Explanation:

Mass of pendulum bob, m=0.453 kg

Speed, [tex]v_1=[/tex]2.58 m/s

a.r=75.1 cm=[tex]75.1\times 10^{-2}m[/tex]=0.751 m

[tex] 1cm=10^{-2} m[/tex]

Tension in the pendulum cable is given  by

Tension=Centripetal force+force due to gravity

[tex]T=\frac{mv^2}{r}+mg[/tex]

Where [tex]g=9.8 m/s^2[/tex]

Substitute the values

[tex]T=\frac{0.453(2.58)^2}{75.1\times 10^{-2}}+0.453\times 9.8[/tex]

[tex]T=8.45 N[/tex]

b.When the pendulum reaches its highest point,then

Final velocity, [tex]v_2=0[/tex]

According to law of conservation of energy

[tex]mgh_1+\frac{1}{2}mv^2_1=mgh_2+\frac{1}{2}mv^2_2[/tex]

[tex]gh_1+\frac{1}{2}v^2_1=gh_2+\frac{1}{2}v^2_2[/tex]

[tex]h_1=0[/tex]

Substitute the values

[tex]9.8\times 0+\frac{1}{2}(2.58)^2=9.8\times h_2+\frac{1}{2}(0)^2[/tex]

[tex]3.3282=9.8h_2[/tex]

[tex]h_2=\frac{3.3282}{9.8}=0.34 m[/tex]

The angle mad  by cable with the vertical=[tex]cos\theta=\frac{0.751-0.34}{0.751}=0.55[/tex]

[tex]\theta=cos^{-1}(0.55)=56.6^{\circ}[/tex]

c.When the pendulum reaches at highest point then

Acceleration, a=0

Therefore, the tension  in the pendulum cable

[tex]T=mgcos\theta[/tex]

Substitute the values

[tex]T=0.453\times 9.8cos56.6[/tex]

[tex]T=2.4 N[/tex]