A train whistle produces a sound at a frequency of 600 Hz. If the train is moving toward a stationary observer at a constant speed, which of the following may be the frequency of the whistle as detected by the observer?

Acompound machine is also called a machine. a. force b. simple c. complex d. directional

Acarpenter builds an exterior house wall with a layer of wood 2.9 cm thick on the outside and a layer of styrofoam insulation 2.3 cm thick on the inside wall surface. the wood has k=0.080w/(m⋅k), and the styrofoam has k= 0.010 w/(m⋅k). the interior surface temperature is 19.0 ∘c , and the exterior surface temperature is -15.0 ∘c . a.)what is the temperature at the plane where the wood meets the styrofoam? celsius b.)what is the rate of heat flow per square meter through this wall? /m^2

What is the increase in density of a medium due to wave travel?