1 Place each of the following musical instruments into one of three groups - hit, plucked and blown - depending on the way in which they produce sound.
trumpet, mandolin, piano, guitar, cello, recorder, drum, harmonica, saxophone
Describe what we can do to increase the loudness of the sounds produced by each instrument.

At a certain instant after jumping from the airplane a, a skydiver b is in the position shown and has reached a terminal (constant) speed vb = 52 m/s. the airplane has the same constant speed va = 52 m/s, and after a period of level flight is just beginning to follow the circular path shown of radius ρa = 2330 m. (a) determine the velocity and acceleration of the airplane relative to the skydiver. (b) determine the time rate of change of the speed vr of the airplane and the radius of curvature ρr of its path, both as observed by the nonrotating skydiver.

When using the scientist method, which step comes last?

Positive ions differ from neutral atoms in that