A. While walking on a level surface, a person exerts a force F of 100 lb from the hip joint to the shoe of the forward foot just at the time the forward foot in planted fully. Assume the leg forms an angle of 15 degrees with the vertical. What coefficient of friction is required to prevent the shoe from slipping on the floor

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.