2.according to newton’s first law, if no force acts on an object, it will just continue moving. explain in terms of newton’s first law why a car engine must exert a force between the car and the road to drive at a constant speed on a straight and level road.

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