Final answer:
The amplitude of y = -2sin(9x) is 2. This is a maximum displacement from equilibrium and the negative sign does not affect the amplitude value.
Step-by-step explanation:
The amplitude of the function y = -2sin(9x) is the coefficient of the sine function, which represents the maximum displacement from the equilibrium position. Here, the amplitude is 2, despite the negative sign, which indicates a phase shift rather than affecting the amplitude.
For the wave equation y(x, t) = 3.00 cm sin (2 m¯¹x − 4 s¯¹t), the amplitude would be 3.00 cm. To find the height at a specific position and time, you would substitute x = 3.00 m and t = 10.0 s into the equation.
When two sine waves with the same amplitude A and a phase difference of 180° interfere, they cancel each other out, resulting in a resultant amplitude of 0 (option c).