What waves are used to penetrate solids and are used in doctor's offices and as airports?

25pts the diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

The 10-kg double wheel with radius of gyration of 125mm about o is connected to the spring of stiffness k = 600 n/m by a cord which is wrapped securely around the inner hub. if the wheel is released from rest on the incline with the spring stretched 225 mm, calculate the maximum velocity v of its center o during the ensuing motion. the wheel rolls without slipping

How do you tell if someone actually cares about you? and just say they do?