How many years does it take for 1/4 of a carbon-14 atom to decay?

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.

What is the average speed of a car that travels 40mph for 1 hour and 60 mph in another hour will mark brainliest

Sunidhi made a study chart about changes in states of matter. which headings best complete the chart?