What are two ways in which ultrasound technology produces images? A. By using sound in frequencies that reflect off body tissues
B. By detecting the frequencies of emitted sound waves
O C. By the absorption of sound waves in the body
U
D. By measuring the time it takes for reflected sound waves to be
detected
SUBMIT

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s