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A 20 kg child is on a swing that hangs from 2.4-m-long chains. part a what is her maximum speed if she swings out to a 44 ∘ angle?

Respuesta :

Answer;

= 3.63 m/s

Explanation;

  • The speed reaches its maximum V when the swing arrives at its vertical position. At that very moment its kinetic energy is  mV^2/2.  
  • In the initial position the potential energy is mgL(1-cosA), where L is the length, and  A is the maximum angle.
  • Considering that the potential energy is zero in the vertical position. Conservation of energy requires that ;

mV^2/2=mgL(1-cosA)  

Thus;  

V=sqrt[(2gL(1-cosA)]

 = √[2 × 9.8 × 2.4 × (1 - cos 44)]

 = √ 13.202

= 3.63 m/s

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