Starting at its rightmost position, it takes 2 seconds for the pendulum of a grandfather clock to swing a horizontal distance of 18 inches from right to left and 2 seconds for the pendulum to swing back from left to right. which of the following equations models d, the horizontal distance in inches of the pendulum from the center as a function of time, t, in seconds? assume that right of center is a positive distance and left of center is a negative distance. d = 9 cosine (startfraction pi over 4 endfraction t) d = 9 cosine (startfraction pi over 2 endfraction t) d = 18 cosine (startfraction pi over 4 endfraction t) d = 18 cosine (startfraction pi over 2 endfraction t)

Respuesta :

The expression that models d, the horizontal distance in inches of the pendulum from the center as a function of time, t, in seconds is d=9cosine[(π/2)t] option second is correct.

What is the frequency?

It is defined as the number of waves that crosses a fixed point in one second, known as frequency. The unit of frequency is per second.

The pendulum takes 2 seconds to swing a horizontal distance of 18 inches from right to left.

For swing back from left to right, it takes again 2 seconds to cover a horizontal distance of 18 inches.

The total time to complete the one cycle = 4 seconds

Thus, the frequency is the reciprocal of the time

f = 1/4

The expression for the angular speed is:

w = 2πf

w = 2π(1/4)

w = π/2

The distance of the pendulum from the center A = half the horizontal                                  

                                                                                 distance of 18 inches

A = 18/2

A = 9 inches

We know the cosine function for the pendulum is given by:

d = Acosine(wt)

d = 9cosine(πt/2)  or

d = 9cosine[(π/2)t]

Thus, the expression that models d, the horizontal distance in inches of the pendulum from the center as a function of time, t, in seconds is d = 9cosine[(π/2)t]

Learn more about the frequency here:

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