An object moving with a speed of 35 m/s and has a mass of 75kg what is the kinetic energy

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.

Ais useful when you need a simple machine to you separate two things. a. lever b. screw c. pulley d. wedge

Which best represents the law of conservation of mass ?