EF 151 Final Exam - Spring, 2016 Page 1 Copy 1

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1 EF 151 Final Exam - Spring, 016 Page 1 Copy 1 Name: Section: Instructions: Sit in assigned seat; failure to sit in assigned seat results in a 0 for the exam. Put name and section on your exam. Put seating label on your equation sheet. Do not open the test until you are told to do so. Completely color in the dot for your multiple choice answers. 11:10 1:40 Write your final answers in the boxes proided for the longer problems. If you finish with less than 5 minutes remaining, please stay seated until the exam is oer. Stop work immediately when time is oer; working after time is oer results in an automatic point deduction :10 Pass exams to the aisle; stay seated until all exams are collected A10 Rachel B10 Rachel C10 Rachel A16 Connor B16 Connor C16 Connor A17 Tayler B17 Tayler C17 Tayler Guidelines: Assume 3 significant figures for all gien numbers unless otherwise stated Show all of your work no work, no credit Include units for all answers and directions for all ectors Solid sphere I mr 5 Solid cylinder 1 I z mr Hollow sphere I mr 3 Hollow cylinder I mr Solid rectangular plate I center 1 1 m h w Solid circular plate I I z x 1 mr 1 I y mr 4

2 EF 151 Final Exam - Spring, 016 Page Copy 1 1. (1 pt) Enter the EXAM ID from your seating label. If you don t know your exam ID, enter Digit #1 Digit # Digit #3 4. (1 pt) What does the area under a elocity time cure represent? Final Acceleration Acceleration Final Position Position Final Velocity Velocity 5. (1 pt) For D motion, which statement must be true for an object s minimum x position? x = 0 y = 0 x = 0 y = 0 ax = 0 ay = 0 6. (1 pt) Lazydog runs with a elocity of m/s and has an acceleration of m/s. Which statement is true about the dog s speed? Not Enough Information Speeding Up Slowing Down Not Changing 7. (1 pt) At impending motion, how do you calculate the friction force of a system? Using only the FBD Friction Force = sn Friction Force = kn Friction Force = m a 8. (1 pt) Which quantity does air resistance (drag) NOT depend upon? Density of air The object s cross-sectional area 9. (1 pt) Which is not a ariable in the ideal projectile motion trajectory equation? 10. (1 pt) Which is NOT one of Newton s three laws of motion? Drag coefficient Velocity Graity Launch angle Initial position Final position Graity Time Initial elocity An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. The acceleration of an object is directly proportional to the magnitude of the net force and inersely proportional to the mass of the object. For eery action, there is an equal and opposite reaction. Energy can neither be created nor destroyed; rather, it transforms from one form to another.

3 EF 151 Final Exam - Spring, 016 Page 3 Copy (1 pt) If all three collisions in the figure shown here are perfectly inelastic, which bring(s) the car on the left to a halt? 1. (1 pt) What does the area under a force time cure represent? Final Acceleration I II III All Acceleration Final Momentum Momentum Work Work II I III m m m m m 0.5 m 13. (1 pt) Which is NOT a alid unit for power? hp Watt BTU/hr J/s ft-lb/s kw-hr kg-m /s (1 pt) Which point best represents this object s center of mass? A B C 15. (1 pt) A 1 inch diameter disk is spinning at 30 rad/sec. What is the linear speed of a point on the edge of the disk? A B C 15 ft/s 15 rpm 30 ft/s 30 rpm 60 ft/s 60 rpm 16. (1 pt) Two pulleys are connected by a belt. The angular speed of the large pulley is 7 rad/sec. What is the angular speed of the small pulley? 56 rad/sec 8 rad/sec 7 rad/sec 1.75 rad/sec r 1 = 8 cm r = cm 17. (1 pt) A system has an angular acceleration of 3. rad/sec and a mass moment of inertia of 1.14 kg-m. What is the magnitude of the net torque acting on the system?.81 N-m N-m 3.65 N-m 0 N-m

4 EF 151 Final Exam - Spring, 016 Page 4 Copy (3 pts) What is the magnitude of the sum of these two ectors? A = 4i + 5j N B = i 13j N 19. (3 pts) A Prius goes from 0 to 60 mph in 1 seconds. How far did it trael during those 1 seconds? 0. (3 pts) You are asked to replace the grass in Neyland stadium? The field requires 1.8 acres of grass, grass costs 33 cents per square foot, and a nud is $10,000. What is the total cost of the grass in nuds? (1 acre = sq ft) 1. (3 pts) Tayler is walking m/s to the right on a moing sidewalk that is moing 4 m/s to the right. Rachel is walking on the ground 5 m/s to the left. Using right as the positie direction, how fast is Rachel moing with respect to Tayler?

5 EF 151 Final Exam - Spring, 016 Page 5 Copy 1. (3 pts) A box of weight W slides down a rough incline. Its speed is increasing. Draw the correct FBD=KD for this situation. DO NOT write the equations. FBD y x KD θ 3. (3 pts) Mabel the dog weighs 68 N on Earth. How much does Mabel weigh on Neptune? (g N = m/s )? 4. (3 pts) A spring has a total length 7 inches when a 0 lb force is applied to it, and a total length of 9 inches when a 30 lb force is applied to it. What is the spring constant of the spring? 5. (3 pts) A bungee cord (k=150 N/m) starts in its neutral position and is stretched.4 meters in 3.6 seconds. What was the power required to stretch the cord?

6 EF 151 Final Exam - Spring, 016 Page 6 Copy 1 6. (3 pts) Two balls collide as shown with e=0.6. What is the y elocity component of ball B after the collision? A = 13 ft/s W A = 1 lb 10 y 33 x B = 5 ft/s W B = 16 lb A B 7. (3 pts) Prof Schleter is driing his Volt around a 56 ft radius cure with a total acceleration of 0 ft/s and a speed of 33 ft/s. What is his tangential acceleration? 8. (3 pts) When rotating about line A through its center of mass, a 3. kg object has a mass moment of inertia of 1.5 kg-m. If the object is rotated about line B which is 47 cm away and parallel to line A, what is the object s mass moment of inertia about line B? 9. (3 pts) When an ice skater holds her arms out, she spins at 45 rpm and has a mass moment of intertia of.4 slug-ft. By pulling her arms in to her sides, the skater s new mass moment of inertia is 1.04 slug-ft. What is the skater s new rotational speed?

7 EF 151 Final Exam - Spring, 016 Page 7 Copy (7 pts) Tayler rides her horse 3 miles due east, 1 5 west of south, and then 5 miles due south. What direction does she need to ride to return to her starting point? 31. (7 pts) Rachel starts from rest and accelerates at a constant rate of 0.4 m/s until she reaches a speed of m/s. She then starts slowing down and stops after another 30 seconds. What is the total distance she traelled?

8 EF 151 Final Exam - Spring, 016 Page 8 Copy 1 3. (7 pts) To celebrate the end of the semester, Connor shoots his physics book into the air at an angle of 4 aboe horizontal. After 1.8 seconds, the book is at y=3.5 ft. What is the book s x position at this time? Use a coordinate system where the initial position of the book is x=0, y=0. (neglect air resistance) 33. (7 pts) Dr. McCord uses a golf cart (combined weight of 500 lb) to pull her 150 lb egetable wagon. The cart s wheels proide a tractie force of 00 lb. The wheels lock up on the wagon, causing a friction force. If the force in the coupling between the cart and wagon is 133 lb, what is the magnitude of the friction force on the wagon? ( FBD=KD required) Wagon Golf Cart

9 EF 151 Final Exam - Spring, 016 Page 9 Copy (7 pts) Block A and Block B are attached to a pulley system as shown. Block B starts from rest at a height, h, aboe the floor. What is h if block B s speed is 6.4 ft/s just before it hits the floor? 9 lb, 6 radius solid disk pulley B 15 lb h 7 lb A 35. (7 pts) Find the total moment about point A from the three forces. 9 N 15 N 55 o. m 3.1 m N 1.4 m A

10 EF 151 Final Exam - Spring, 016 Page 10 Copy (7 pts) The coefficient of restitution for this 1D direct collision is What is the elocity of the kg object after the collision? x kg 13 m/s 4 m/s 7 kg