Q1. The rotational inertia of a collapsing spinning star changes to 4/5 its initial value. What is the ratio of new rotational kinetic energy to the initial rotational kinetic energy (KEnew / KEi)?
Q2. A motorist drives south at 27.0 m/s for 3.90 min, then turns west and travels at 25.0 m/s for 2.40 min, and finally travels northwest at 40.0 m/s for 1.00 min. For this 6.40 min trip, find the values.
(a) Total vector displacement m (magnitude) south of west
(b) average speed
(c) average velocity (magnitude) south of west