According to the graph, what is the maximum age at which a 4000 Hz sound wave with an intensity of 20 dB would be heard?

55
60
65
70

What are the phases shown in a and d called?

Asmall object with mass 0.200 kg swings back and forth on the lower end of a light rope that is 3.00 m long. the upper end of the rope is attached to the ceiling. as the object swings through its lowest position, where the rope is vertical, the speed of the object is 5.80 m/s. at this point in the motion, what is the tension in the rope? (use g = 9.80 m/s2.)

The energy equivalent of the rest mass of an electron is