PROBLEMS NOT FROM GIAMBATTISTA
                               
        CHAPTER 10
        A5. A tray is moved horizontally back and forth in SHM at 
            a frequency of 2.00 Hz.  On this tray is an empty cup.  
            Obtain the coefficient of static friction between the 
            tray and the cup, given that the cup is observed to 
            begin slipping when the amplitude of the motion is 
            5.00 cm.
            
        A6. The front spring of a car's suspension system has a
            spring constant of 1.5 million N/m and supports an
            effective mass of 215 kg.  The wheel has a radius of 
            0.400 m.  The wheel is slightly unbalanced and wobbles 
            once each revolution.  Due to resonance, the wheel 
            starts to vibrate strongly when the car is traveling 
            at a certain linear speed.  What is this speed?

        A7. A source moving through water at 10 m/s generates
            water waves with a frequency of 5.0 Hz.  The speed of
            these water waves relative to the water surface is
            20.0 m/s.  The source is receding from an observer who 
            is at rest in the water.  (a) What wavelength would be
            measured for these waves by the stationary observer?
            For that observer, how much time elapses between the 
            arrival of one crest and the next?  (b) Answer the
            same two questions if the source is stationary and
            the observer is moving away from the source at 10 m/s.

        A8. The G string of a violin has a fundamental frequency
            of 196 Hz.  It is 30.0 cm long.  While this string is
            sounding, a nearby violinist effectively shortens (by
            sliding her finger down the string) the G string on 
            her identical violin until a beat frequency of 2.00 Hz
            is heard between the two strings.  When this occurs, 
            what is the effective length of her string?