What is buoyant force? a. a force within a fluid that pushes downward b. the attraction between two identical molecules c. the attraction between two different molecules d. a force within a fluid that pushes upward

50.)the diagram below represents the wave fronts produced by a point source moving to the right in a uniformmedium. observers are located at points a and b.compared to the wave frequency and wavelength observed at point a, the wave observed at point b has a(1) higher frequency and a shorter wavelength(2) higher frequency and a longer wavelength(3) lower frequency and a shorter wavelength(4) lower frequency and a longer wavelength