Name: Class: Date: v f 2 = v i 2 + 2a x. v f = v i 2 + 2a x = x = v i t a( t)2 = v i t ( g)( t)2

Transcription

1 Assessment Chapter Test B Teacher Notes and Answers Motion in One Dimension CHAPTER TEST B (ADVANCED) 1. a 2. b 3. c 4. a 5. b 6. b 7. a 8. c 9. d 10. c 11. b 12. Although the magnitudes of the displacements are equal, the displacements are in opposite directions. Therefore, one displacement is positive and one displacement is negative. 13. The displacement is negative because a change of position in the direction opposite of increasing positive position is negative displacement. 14. The dog s initial position and its final position are the same position. 15. Since the usual choice of coordinates uses positive as the direction away from Earth, the direction of free-fall acceleration is negative because the object accelerates toward Earth h v avg = 1.8 km/h x = 0.30 km v avg = x t t = x 0.30 km = v avg 18 km/h = h km, north v avg,1 = 0.75 km/h t 1 = 1.5 h v avg,2 = 0.90 km/h t 2 = 2.5 h x = x 1 + x 2 = v avg,1 t 1 + v avg,2 t 2 x = ( 0.75 km/h)(1.5 h) + (0.90 km/h) (2.5 h) = 1.2 km, north m/s v i = 1.8 m/s a = 3.00 m/s 2 x = 0.37 m v f 2 = v i 2 + 2a x v f = v i 2 + 2a x = (1.8 m/s) 2 + (2)( 3.0 m/s 2 )(0.37 m) v f = 1.0 m/s 19. at least 0.20 m a = g = 9.81 m/s 2 t = 0.20 s v i = 0.0 m/s x = v i t a( t)2 = v i t ( g)( t)2 x = (0 m/s)(0.20 s) ( 9.81 m/s2 )(0.20 s) 2 = 0.20 m Holt Physics 1 Chapter Tests

2 m a = g = 9.81 m/s 2 v i,1 = 0.0 m/s x = 32.0 m v i,2 = 0.0 m/s t 1,2 = 2.0 s x 1 = v i,1 t a( t 1 )2 t 1 = 2 x 1 a = 2 x 1 g = 2( 32.0 m) 9.81 m/s = 2.56 s 2 t 2 = t 1 t 1,2 = 2.56 s 2.00 s = 0.56 s x 2 = v i,2 t a( t 2 )2 = v i,2 t ( g)( t 2) 2 x 2 = (0.0 m/s)(0.56s) ( 9.81 m/s2 )(0.56 s) 2 = 1.5 m h = 32.0 m 1.5 m = 30.5 m Holt Physics 2 Chapter Tests

3 Assessment Motion in One Dimension Chapter Test B MULTIPLE CHOICE In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. Which of the following is the equation for average velocity? a. v avg = x c. v t avg = x t b. v avg = t x Use the graph below to answer questions 2 4. d. v avg = v i v f 2 2. During which interval is the cat at rest? a s c s b s d s 3. The cat has the fastest speed during which interval? a s c s b s d s 4. During which interval does the cat have the greatest positive velocity? a s c s b s d s 5. Which of the following is the equation for acceleration? a. a = t c. a = v t v b. a = v t d. a = v i v f t i t f Holt Physics 3 Chapter Tests

4 Chapter Test B continued 6. When a car s velocity is negative and its acceleration is negative, what is happening to the car s motion? a. The car slows down. b. The car speeds up. c. The car travels at constant speed. d. The car remains at rest. 7. What does the graph on the right illustrate about acceleration? a. The acceleration varies. b. The acceleration is zero. c. The acceleration is constant. d. The acceleration increases then becomes constant. 8. In the graph on the right, how does the acceleration at A compare with the acceleration at B? a. The acceleration at A is positive and less than the acceleration at B. b. The acceleration at B is positive and less than the acceleration at A. c. The accelerations at A and B are each zero. d. The accelerations at A and B cannot be determined. 9. Which of the following line segments on a velocity versus time graph is physically impossible? a. horizontal line b. straight line with positive slope c. straight line with negative slope d. vertical line 10. In the graph at the right, at what point is the speed of the ball equal to its speed at B? a. A b. C c. D d. none of the above Holt Physics 4 Chapter Tests

5 Chapter Test B continued 11. A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball s path does it experience zero velocity and nonzero acceleration at the same time? a. midway on the way up b. at the top of its path c. the instant it leaves the catcher s hand d. the instant before it arrives in the catcher s mitt SHORT ANSWER 12. Distinguish between the displacement of a traveler who takes a train from New York to Boston and the displacement of a traveler who flies from Boston to New York. Be sure to compare the magnitudes of the displacements. 13. If a runner moves from a positive position to a negative position, explain if the runner s displacement is negative or positive. 14. Explain how a dog that has moved can have a displacement of zero. 15. Why is the direction of free-fall acceleration usually negative? PROBLEM 16. A biker travels at an average speed of 18 km/h along a 0.30-km straight segment of a bike path. How much time does the biker take to travel this segment? Holt Physics 5 Chapter Tests

6 Chapter Test B continued 17. A hiker travels south along a straight path for 1.5 h with an average speed of 0.75 km/h and then travels north for 2.5 h with an average speed of 0.90 km/h. What is the hiker s displacement for the total trip? 18. A skater glides off a frozen pond onto a patch of ground at a speed of 1.8 m/s. Here she is slowed at a constant rate of 3.00 m/s 2. How fast is the skater moving when she has slid 0.37 m across the ground? 19. Human reaction time is usually about 0.20 s. If your lab partner holds a ruler between your finger and thumb and releases it without warning, how far can you expect the ruler to fall before you catch it? (Disregard air resistance. a = g = 9.81 m/s 2.) 20. A pair of glasses are dropped from the top of a 32.0 m high stadium. A pen is dropped 2.00 s later. How high above the ground is the pen when the glasses hit the ground? (Disregard air resistance. a = g = 9.81 m/s 2.) Holt Physics 6 Chapter Tests