Ultrasound being used to study an unborn baby.
ultrasound receiver Source ultrasound
beam
(a) Describe how the vibrations of the source produce waves of ultrasound and how these waves are transmitted through the body tissues to the receiver,
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An object is moving east, and it’s velocity changes from 65m/s to 25m/s in 10 seconds. which describes the acceleration?

Write the equation for momentum, first using symbols for the variables, then using words for the variables.

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.