Hot exhaust gases leaving a stationary diesel engine at 450°c enter a 15-cm-diameter pipe at an average velocity of 3.6 m/s. the surface temperature of the pipe is 180°c. determine the pipe length if the exhaust gases are to leave the pipe at 250°c after transferring heat to water in a heat recovery unit. use properties of air for exhaust gases.

Bob camina 200 m sur, luego trota 400 m suroeste, luego camina 200 m en una dirección 30? norte del este. a. dibuje una gráfica de los movimientos de bob. use una regla y transportador. b. use método gráfico y analíitico para hallar el desplazamiento total que bob recorrió. (magnitud y dirección) c. compare los resultados obtenidos por el método gráfico y analítico. (por ciento de diferencia).

The of a machine determines its "usefulness." a. input force b. output force c. mechanical advantage

A23 kg log of wood begins from rest, 300 m up a sluice (a water track used to transport logs, think of it as an inclined plane with negligible friction) inclined at 20° to the horizontal. after it reaches the flat waterway at the bottom it collides elastically with a 100 kg block of wood initially at rest near the base of the incline. (a) how long does it take the 23 kg log to travel down the incline? (b) what is the speed of the 23 kg log at the bottom of the incline? (c) what are the velocities of both blocks of wood after the collision? (d) what is the total kinetic energy before the collision? (e) what is the kinetic energy of the 23 kg log after the collision? (f) what is the kinetic energy of the 100 kg block of wood after the collision? (g) what is the total kinetic energy after the collision? (h) compare the total initial and total final kinetic energies. is this consistent with what you would expect for elastic collisions? explain!