Need help with 6, 7 and 8 please help and I will mark brainliest

Wo audio speakers are placed on a vertical rail. speaker a is placed at head-level while speaker b is place at some variable height, \delta yδy, above speaker a. both speakers receive simultaneous input from a sine-wave generator so the speakers each produce a pure sinusoidal sound wave with a wavelength of 0.531 meters. calculate the lowest height that speaker b can be placed above speaker a to produce a minimum of sound heard by person standing \delta x = 7.86δx=7.86 meters directly in front of speaker a.

From the perspective of an employee that effective channeling of work related information and concerns

What is the measure of how much matter is in an object and that can be measured using a balance? a. height b. volume c. weight d. mass