Answer:
a) The sinusoidal equation is;
The function is h = -24·cos[π(t )] + 24
The sketch of one full revolution is attached
b) The height of the nail at 0.8 seconds is 43.42 cm
Step-by-step explanation:
The sinusoidal equation that models the nails height can be given as follows;
y = A·cos[B(x - C)]+D
A = The amplitude = Half maximum height = 48/2 = 24 cm
The period = 2·π/B = Time to complete one oscillation = 2 seconds
∴ B = 2·π/2 = π
x = t = Time
C = The horizontal shift
D = the vertical shift = 24 cm
y = The height of the nail = h
We have;
h = -24·cos[π(t - C)] + 24
At t = 0, h = 0, therefore, we have;
0 = -24·cos[π(0 - C)] + 24
24·cos[π(0 - C)] = 24
∴ cos[π(0 - C)] = 24/24 = 1
π(0 - C) = 0
C = 0
The function is h = -24·cos[π(t )] + 24
b) The height of the nail at 0.8 seconds is given as follows;
h = -24×cos[π(0.8)] + 24 =
h = 19.42 + 24 = 43.42 cm.
