Newton's law of cooling states that d x d t = − k ( x − a ) where x is the temperature, t is time, a is the ambient temperature, and k > 0 is a constant. suppose that a = a 0 cos ( ω t ) for some constants a 0 and ω . that is, the ambient temperature oscillates (for example night and day temperatures). a) find the general solution. b) in the long term, will the initial conditions make much of a difference? why or why not?

In a wind tunnel the speed changes as the cross sectional area of the tunnel changes. if the speed in a 6' x 6' square test section is 100 mph, what was the speed upstream of the test section where the tunnel measured 20' x 20'? use conservation of mass and assume incompressible flow. conservation of mass requires that as the flow moves through a path or a duct the product of the density, velocity and cross sectional area must remain constant; i.e., that ova-constant. a model is being tested in a wind tunnel at a speed of 100 mph if the flow in the test section is at sea level standard conditions, what is the pressure at the model's stagnation point? (a) the tunnel speed is being measured by a pitot-static tube connected to a u- tube manometer. what is the reading on that manometer in inches of water? (b) at one point on the model a pressure of 2058 psf is measured. what is the local airspeed at that point?

Acalorimeter uses the principle that thermal energy flows from hotter material to colder material until both reach the same

Gabby calls her cousin who lives in a different state and tells her to turn her radio to channel 98.7 so they can listen to their favorite song that is playing. her cousin turns her radio to 98.7, but does not hear the same song gabby hears. which most likely explains why?