Ultrasound is the name given to frequencies above the human range of hearing, which is about 20,000 hz. waves above this frequency can be used to penetrate the body and produce images by reflecting from surfaces. in a typical ultrasound scan, the waves travel with a speed of 1,809 m/s. for a good detailed image, the wavelength should be no more than 1.44 mm. what frequency is required?

Find the vertex(use the completing the square method), findthe x- and y-intercepts, and sketch the graph offunction. y = 2x2 + 4x - 1

Which is special about a dc circuit ? a. it has both series and parallel components b. it has only series or only parallel components c. charge moves in a single direction d. charge moves back and forth quickly

Acommercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -35°c by rejecting waste heat to cooling water that enters the condenser at 18°c at a rate of 0.25 kg/s and leaves at 26°c. the refrigerant enters the condenser at 1.2 mpa and 50°c. if the compressor consumes 3.3 kw of power, determine (a) the mass flow rate of the refrigerant, (b) the refrigeration load, (c) the cop, and (d) the minimum power input to the compressor for the same refrigeration load.