8.Mass is a quantitative measure of an object's inertia. 10.The football player whose mass is 110 kg will have more difficulty. He has more inertia, so it will be more difficult to change his motion (a is inversely related to mass). DAY 5: P.63 Problems 5.vf = 11 m/s and 7.F = 23 N DAY 6: P.63 Problems 2.F = 6.00 kg; 2.Fw = 4.90 x 102 N; 3.Fw=113N DAY 7: P.85 Problems 1.mu = 0.227; 2.Ff = 4.0 N DAY 8: P.84 Questions 1.Friction, a force that opposes motion, involves objects that are in contact with each other. 4.Opposite the direction of the object's motion. 5.Friction depends on the nature of the materials and the normal force pressing the objects together. 7.(a)The coefficient of friction decreases. (b)Since the frictional force is less, it will take longer to stop, therefore the driver needs to begin braking earlier. 10.(a)increases; (b)decreases; (c)decreases DAY 11: P.62-3 Questions 5.Student diagram. The net force on the book is zero. 6.Yes, friction. 7.Student diagram. Yes, there is now no forward force balancing the force of friction pulling backward.