This Post Has 3 Comments

1. Both A and B is true

   Explanation:

   Given system is friction less

   Consider a system of spring mass-system with general displacement equation

   [tex]x=A\sin \omega t[/tex]

   where A=maximum amplitude

   [tex]\omega[/tex]=frequency of oscillation

   [tex]t=time[/tex]

   [tex]v=A\omega cos\omega t[/tex]

   Total Energy of the system is E=Potential Energy(U)+kinetic Energy(K)

   At max amplitude

   i.e. [tex]A=A\sin\omega t[/tex]

   [tex]\omega t=\frac{\pi }{4}[/tex]

   [tex]t=\frac{\pi }{4\omega }[/tex]       [tex](T\cdot \omega =2\pi )[/tex]

   where T = time period for one complete oscillation

   [tex]t=\frac{T}{4}[/tex]

   at [tex]t=\frac{T}{4}[/tex]

   [tex]v=0[/tex]

   thus [tex]k=0[/tex] and [tex]U=E[/tex]

   i.e. Maximum at maximum amplitude

   B.at mean position [tex]x=0[/tex]

   [tex]\omega t=\pi[/tex]

   [tex]t=\frac{T}{2}[/tex]

   [tex]v=v_{max}[/tex] i.e. total Energy is equal to Kinetic energy and Potential Energy is zero

   hence B is true.

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2. Answer:

   the word that best describes martin luther king jr.'s tone in the video is dignified

   explanation:

   martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer

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3. i need my girl back keith uses i need my girl back

   explanation:

   my daughter rae

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