How many electrons does magnesium have when it is electrically neutral?
how many protons does iron have when it is electrically neutral?

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.

Aregion of space in which a measurable gravitational force is indicated by the force exerted on a test mass is called

Match each type of lever with the correct diagram. 1. first-class 2. third-class 3. second-class