The process of recording sound waves as they bounce off the heart; a picture is produced that shows the sound waves as they are reflected from tissues of different densities:

Explain why the aperture of the spherical mirror should be small compared to the radius of curvature of the mirror.

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

Agirl throws a ball. if the ball's acceleration is 12 m/sec/sec and its mass is 0.5 kg, how much force did the girl apply to the ball?