Which of the following is true about ultrasound imaging and human hearing?

What does acoustic impedance depend on?

Spectral Doppler is useful for:

Duty Factor is defined as:

What frequency range qualifies sound as ultrasound?

What are compressions in a sound wave?

A spring is attached to points A and B as shown in the figure.  The spring constant, k, is given equal to k = 100 N/m and it is stretched by s = 0.1m.  Distance b = 2 m. Consider the force which the spring exerts on point A only and calculate the moment it produces about the coordinate axes x and y.    Calculate the moment produced by the same force about axis OB. You need to show the expression using numerical values; however, you do not need to complete the calculations to find the value of the moment.

Determine the resultant force of forces F2  and F3 as a cartesian vector.  Note that the angles shown in the force F2 are the coordinate angles α, β and γ with respect to the coordinate axes. You may ignore force F1. 

The structure is supported by two pins at points A and B and a roller at point F. It is subjected to a distributed load at segment CG, two point loads and a couple moment, as shown in the figure. Calculate the support reactions at points A, B, and F and the forces at the internal pins at C and D. Show all your work including a Free Body Diagram to receive full credit.

The shaft is supported by a journal bearing at A and a thrust bearing at B. Determine the tension in cable CE and the reactions at A and B when a load P = 110 lb and a couple moment M = 40 lb·in is applied. Assume the bearings are properly aligned. For full credit, you must show these steps: Draw a free body diagram. Write sum of forces acting on the body. Take the sum of moments about point B.