A 4 kg block is at rest on a table. The coefficient of static friction between the box and the table is 0.30 and the coefficient of kinetic friction is 0.10 . Then a 10 N horizontal force is applied to the box. What is the acceleration of the box? (Use 9.8 m/s/s for the acceleration due to gravity).

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s. part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.