Atrain moves at a constant velocity of 50 km/h. how far will it move in 0.05 h?

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.

Which type of bond is found between the atoms of a molecule? a. metallic b. delocalized electron c. covalent d. ionic

It is really hard for me right know