Physics, 21.08.2019 16:30 angeline2004
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?
Answers: 1
Physics, 21.06.2019 23:30, hardwick744
Which lists the main components of darwin’s theory of evolution? a. random mutations drive evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms do not change. b. natural selection drives evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms change over time. c. natural selection drives evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms change over time. d. random mutations drive evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms do not change.
Answers: 1
Physics, 22.06.2019 04:10, brianamelara
Atotal charge of –6.50 µc is uniformly distributed within a sphere that has a radius of 0.150 m. what is the magnitude and direction of the electric field at 0.300 m from the surface of the sphere? a) 2.89 × 105 n/c, radially inward b) 6.49 × 105 n/c, radially outward c) 4.69 × 105 n/c, radially inward d) 9.38 × 105 n/c, radially outward e) 1.30 × 106 n/c, radially inward
Answers: 3
Physics, 22.06.2019 11:00, sudotoxic
Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?
Answers: 2
Ultrasound is the name given to frequencies above the human range of hearing, which is about 20,000...
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