1. CP Physic Chapter 5 Review 1. The coefficient of kinetic friction is ______ the coefficient of static friction? ans: less than 2. Which of the following is the Law of Cosines? R 2 = a 2 + b 2 or R 2 = a 2 + b 2 – 2abcosѲ ans: R 2 = a 2 + b 2 – 2abcosѲ 3. To calculate the force of static friction you will need the force normal and ____ ans: coefficient of static friction

2. 4. The law of sines is ans: c = a = b sinC sin A sin B 5. An object has a mass of 5.5 Kg. What is the force normal, F N ans: F N = Fw = mg ; F N = 5.5 Kg( 9.8m/s 2 ) 6. A man pulls a weight of 340 N across a surface. If the force of motion is 17 N, what is the coefficient of friction? ans: μ k = F k / F N ; 17N / 340N = 0.05

3. 7. An object has a mass of 76 Kg and the coefficient of static friction is 0.18. What is the maximum force of static friction? ans: μ s = F s / F N ; F s = 745N(0.18) = 134.1N 8. If a box slide across the floor to the right, in what direction is the force of friction? ans: to the left 9. A force of 15N pulls east and a force of 12 N pulls west. What is the resultant vector? ans: 3N east

4. 10. A box is pulled across the floor with a force of 50N that makes a 21 o angle to the floor. a. Draw a free body diagram of this situation. b. What is the force along the horizontal or x-axis? ans: Fx = 50Ncos21 = 46.7N c. What is the force along the vertical or y-axis? ans: Fy = 50Nsin21 = 17.9N d. What will happen to Fx and Fy if the angle was decreased? ans Fx will increase; Fy will decrease

5. 11. A hiker walks 2 Km due west then takes a 28 o turn from his path to the south and walks another 1.5 Km. a. Draw a free body diagram: b. Find the resultant. ans: 3.4 Km c. What is the angle the hiker will walk from his 1.5 Km path to walk back to his starting point? ans: 16.1 o

6. 12. A 2.3 Kg box is pushed across the floor with a force to a final velocity of 8.4 m/s. If the box slides for 12.4 m before coming to rest, what is the coefficient of sliding friction? ans: 13. What is the rate of acceleration of a 2 Kg box sliding down a 25 o incline. The coefficient of sliding friction is 0.24. ans:

7. 14. A box with a mass of 5.6 Kg is setting at rest on an incline of 28 o. a. What is the force normal, F N ? ans: b. What is the force parallel, F p ? ans: 15. A dog pulls on a toy at an angle of 23 o to the horizontal with a force of 56N. The toy has a mass of 2.2 Kg. What is the coefficient of sliding friction? ans: