Two cars approach each other from opposite directions each with a velocity of 54 km/hr. One of the cars emits a note of frequency 480 Hz. What will be the approximate frequency heard in the other car before they pass each other? The speed of sound in this situation is 340 m/sec.

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?