una alarma emite ondas del sonido con una frecuencia de 500HZ y una amplitud 0.3m. las ondas viajan a una velocidad de 250m/s ¿cual es la longitud de la onda y el periodo de las ondas emitidas?

True or false when elements combine to form a mixture, the resulting chemical properties may be very different from those of the elements that make it.

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

Aball with a mass of 275 g is dropped from rest, hits the floor and rebounds upward. if the ball hits the floor with a speed of 2.40 m/s and rebounds with a speed of 1.70 m/s, determine the following. (a) magnitude of the change in the ball's momentum (let up be in the positive direction.)