Exam 2--PHYS 101--F11--Chapters 4, 5, & 6

Transcription

1 ame: Exam 2--PHYS 101--F11--Chapters 4, 5, & 6 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Consider this figure. What is the normal force acting on the block? a. 98 N c. 85 N b. 49 N d. 10 N 2. In the figure for the previous problem, what is the coefficient of static friction, between the block and inclined plane, required to keep the block in place? a. 0.6 d. 0.3 b. 0.1 e. 1 c. 49 1

2 3. Which of these statements best describe Aristotle s view of the natural world: a. objects will continue in motion unless an outside force acts on them c. the mass of an object is a measure of its inertia b. all objects are propelled by a mystical force that emanates from the Earth d. all objects have a natural state, which is at rest 4. Which of these make up the basic SI units of the newton? a. kg m kg m c. s kg 2 m 2 kg m 2 b. d. s 2 s 2 5. A force causes this bucket to accelerate upwards as shown. What is the magnitude of the force? s 2 a. 10 N c. 200 N b. 50 N d. 150 N 6. From rest, we step on the gas of our Subaru, providing a force F for 4 secs, travelling a distance of 10 meters. If the applied force were only 1 2 F, how far does the car travel in the same amount of time? a. 10 m d. 15 m b. 20 m e. 5 m c. 2.5 m 7. A block of mass m rests on the floor of an elevator that is accelerating upward. What is the relationship between the force due to gravity (F g ) and the normal force on the block (F N )? a. F N >F g c. F N <F g b. F N =F g d. it depends on the mass of the block 2

3 8. This figure shows a block supported by 2 ropes. What is the tension in the rope on the right? a. 230 N c. 150 N b. 180 N d. 300 N 9. Which of these is a conservative force? I. Gravitational force II. Frictional force III. Electric force IV. Normal Force a. II & IV c. I & III b. I, III, & IV d. I & II 10. Which is usually larger, kinetic or static friction? a. kinetic friction c. they are usually the same b. static friction d. it depends on the mass of the objects 3

4 11. In this figure, all of the blocks have a displacement to the right. The magnitude of the force is the same for each block. Which force is doing the least amount of work? a. a c. c b. b d. d 12. This figure shows two forces acting on a block; the block travels 3.4 meters to the right. What is the net work done on the block by both forces? a. 8.6 J c. 12 J b. 3.7 J d. 16 J 4

5 13. You throw a ball up in the air, and it goes to a height of 16 m. What is the speed of the ball when it is at a position of 8.0 m? a. 13 m/s c. 22 m/s b. 18 m/s d. 5.0 m/s 14. You kick a ball, whose mass is 1.3 kg, at an angle of 43º. You give it an initial velocity of 12 m/s. What is the ball s maximum height? (Hint: Consider the y-component of the ball s initial velocity.) a. 3.4 m c. 7.3 m b. 5.2 m d. 3.9 m 15. A car travels a distance x at acceleration a and does work W. If the car travels a distance 2x at the same acceleration, what is the work it has done? a. W c. 4W b. 2W d. W 16. Which requires more energy: to take a car from 0 30 mi/hr or from mi/hr? a c. both the same b d. it depends on the mass of the car 5

6 17. Consider this figure. Three blocks of mass m slide down different inclined planes, each beginning at a height h. The coefficient of kinetic friction for the inclined planes is 0.3. Which block has the most energy at the bottom of the inclined plane? a. a c. c b. b d. all have the same energy 18. You compress a mass on a spring, as in this figure, and release it. At what position does the mass have its largest speed? a. x=-a c. x=+a b. x=0 d. x= a 6

7 19. A force of 1.0 N pushes a block over a rough, flat surface at a constant speed of 2.0 m/s. The force pushes the block a total distance of 8.0 m. What is the power used to produce this motion? a. 4.0 W c. 2.0 W b. 16 W d W 20. A car is travelling at 22 m/s and crashes into a wall. The collision occurs in 0.10 seconds, and the car rebounds at 2.0 m/s. The mass of the car is kg. What force is exerted on the car in this collision? a. 200,000 N c. 240,000 N b. 22,000 N d. 220,000 N 7

8 21. The following figure shows a perfectly inelastic collision, where the two particles stick together after colliding. What is the final speed of the particles? a m/s c m/s b. 1.3 m/s d m/s 22. Which of these statements is most appropriate for an elastic collision? a. momentum is conserved c. both energy and momentum are conserved b. energy is conserved d. neither energy or momentum are conserved 23. A uranium nucleus (at rest) undergoes fission and splits into two fragments, one heavy and the other light. Which fragment has the greater speed? a. the heavy fragment c. both have the same speed b. the light fragment d. it depends on the energy of the fragments 24. A collection of particles has a total momentum of zero. Which of these statements is true? a. the kinetic energy of the particles must c. the particles have no mass be zero b. the kinetic energy of the particles might be zero, but not necessarily d. the particles are definitely moving 25. The answer to this question is A. a. A c. C b. B d. D 8

9 ID: A Exam 2--PHYS 101--F11--Chapters 4, 5, & 6 Answer Section MULTIPLE CHOICE 1. ANS: C PTS: 1 2. ANS: A PTS: 1 3. ANS: D PTS: 1 4. ANS: C PTS: 1 5. ANS: D PTS: 1 6. ANS: E PTS: 1 7. ANS: A PTS: 1 8. ANS: C PTS: 1 9. ANS: C PTS: ANS: B PTS: ANS: A PTS: ANS: A PTS: ANS: A PTS: ANS: A PTS: ANS: B PTS: ANS: B PTS: ANS: A PTS: ANS: B PTS: ANS: C PTS: ANS: C PTS: ANS: C PTS: ANS: C PTS: ANS: B PTS: ANS: B PTS: ANS: A PTS: 1 1