The rate at which a nebular cloud rotates increases as the cloud collapses to form systems of stars and planets. Consider a small segment of a nebular cloud with a mass of 1.9×1027 kg, tangential velocity initial equal to 6.8 km s−1 located at an orbital distance initial=2.5×104 km. After the cloud collapses, the same small segment is located at an orbital distance final=3.2×103 km. Calculate the change of the rotational velocity, Δ, for the cloud segment, assuming perfectly circular orbits. Perform your work and report your solution using two significant figures.