Ultrasonic imaging is made possible due to the fact that a sound wave is partially reflected whenever it hits a boundary between two materials with different densities within the body. the percentage of the wave reflected when traveling from material 1 into material 2 is r=(ρ1−ρ2ρ1+ρ2)2. knowing this, why does the technician apply ultrasound gel to the patient before beginning the examination?

The temperature at a point (x, y) is t(x, y), measured in degrees celsius. a bug crawls so that its position after t seconds is given by x = 6 + t , y = 8 + 1 3 t, where x and y are measured in centimeters. the temperature function satisfies tx(3, 9) = 5 and ty(3, 9) = 4. how fast is the temperature rising on the bug's path after 3 seconds? (round your answer to two decimal places.)

Brades exam guidelines exam instructions billing & payments & support question 6 of 20 : select the best answer for the question use this illustration to answer the question below. forms & resources al programs 9 ww linics 6. in the circuit shown in the figure above, suppose that the value of r, is 100k, and the value of r2 is 470 kq. at which of the following locations in the circuit would you measure the highest voltage with your meter? rvices 999999 a. between points b and c b. between points a and b c. between points b and e d. between points a and c eredu mark for review (will be highlighted on the review page) mend < < previous question next question

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants