Two speakers create identical
240 Hz sound waves. A person is
1.47 m from Speaker 1. What is the minimum distance to Speaker 2
for there to be destructive
interference at that spot?
(Hint: v= A f = 343 m/s)
(Unit = m)

Which of the following represents an upside-down image?

At what time will the interfering waves have an amplitudeof zero?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".