A weight attached to a spring is at its lowest point, 9 inches below equilibrium, at time t = 0 seconds. When the weight it released, it oscillates and returns to its original position at t = 3 seconds. Which of the following equations models the distance, d, of the weight from its equilibrium after t seconds?

Respuesta :

The motion can be modeled as
[tex]x(t) =9 \, cos( \frac{2 \pi t}{T} )[/tex]
where 
x = the position below the equilibrium position
T =  the period of the motion
t = time

The weight returns to its equilibrium position when x = 0. 
This occurs when
[tex] \frac{2 \pi t}{T} = \frac{ \pi }{2} [/tex]
That is,
[tex]t= \frac{T}{4} [/tex]

Because the weight returns to the equilibrium position when t =  3 s, therefore
T = 12 s
The motion is
[tex]x(t) = 9 \, cos( \frac{ \pi t}{6} )[/tex]

When t = 1 s, the position of the weight from equilibrium is
[tex]d = 9 \, cos( \frac{ \pi }{6} ) = 9( \frac{1}{2} ) = 4.5 \, in[/tex]

Answer:
[tex]d = 9 \, cos( \frac{ \pi }{6} ) = 4.5 \, in[/tex]

Answer:

D=-9cos(2pi/3t)

Step-by-step explanation: