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Q1) A 1.2 kg block sliding on a horizontal frictionless surface is attached to a horizontal spring with k =480 N/m. Let x be the displacement of the block from the position at which the spring is upstretched. At t = 0 the block passes through x = 0 with a speed of 5.2 m/s in the positive x direction. What are the (a) frequency and (b) amplitude of the block’s motion? (c) Write an expression for x as a function of time

Respuesta :

Answer:

Explanation:

given,

mass of block = 1.2 kg

spring constant (k) = 480 N/m

a) Frequency

  [tex]f = \dfrac{1}{2\pi }\sqrt{\dfrac{k}{m}}[/tex]

  [tex]f = \dfrac{1}{2\pi }\sqrt{\dfrac{480}{1.2}}[/tex]

  f = 3.183 Hz

b) The position function

  x = A cos (ωt + ∅)

at t = 0 , x = 0

  0 = A cos ∅

  cos ∅ = 0

    ∅ = π/2

velocity at t= 0 s

[tex]v = \dfrac{dx}{dt}[/tex]

v = Aωsin (ωt + ∅)

[tex]v = A\omega sin ( + \dfrac{\pi }{2})[/tex]

[tex]5.2 = A\sqrt{\dfrac{480}{1.2}}[/tex]

A = 0.26 m

c)   [tex]x = 0.26 cos (\sqrt{\dfrac{480}{1.2}}t + \dfrac{\pi }{2})[/tex]

     [tex]x = 0.26 cos( 20 t +\dfrac{\pi }{2})[/tex]