Tell me why units are important in physics. write down 2 system of measurement in terms of units.

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.

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Question 1 (5 pts): what is the maximum distance for which you can you resolve the two individual headlights of an on-coming truck as two separate lights rather than one if the headlights are separated by 2.00 m and your eye has a diameter of 1.00 centimeter? assume a wavelength of 500 nm.