Answer: x(t) = 5cm*cos(t*pi/2s)
Step-by-step explanation:
This is a sinusoidal equation, so we can write this as:
x(t) = A*cos(c*t + p) + B
where B is the axis around the movement, as the resting position is x = 0, we have B = 0
so x(t) = A*cos(c*t + p)
A is the amplitude of the oscilation, c is the frequency and p is a phase.
We know that when t = 0s, we have x(2s) = 5cm
if this is the maximum displacement, then knowing that the maximum of the cosine is cos(0) = 1
then we must have that p = 0
x(0s) = A*cos(0) = 5cm
then we have A = 5cm
Now, when t = 2s, we have:
x(2s) = 5cm*cos(2s*c) = -5cm
then 2s*c is the minimum of the cos(x) function, this is:
cos(pi) = -1
then 2s*c = pi
c = pi/2s.
then our function is:
x(t) = 5cm*cos(t*pi/2s)