Answer:
v = 2 cm/s
Explanation:
The equation of the wave is
y(x,t) = (2.0cm)*cos(2π*x−4π*t)
Where,
x is measured in cm
t in s
A more general formula for this equation would be
y(x,t) = A*cos(k*x−ω*t)
Where,
A = amplitude.
k = the wavenumber
ω = the angular frequency
The velocity of the wave corresponds to
v = ω/k
v = 4π / 2π = 2 cm/s
v = 2 cm/s