What does a machine change to make work easier? Select three options. the amount of work done
the amount of force applied
the time needed to do the work
o the direction of a force
the distance over which a force is applied

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