front 1 If a vector pointing upward has a positive magnitude, a vector pointing downward has a negative magnitude.
| back 1
|
front 2 Two displacement vectors have magnitudes of 5.0 m and 7.0 m, respectively. If these two vectors are added together, the magnitude of the sum
| back 2
|
front 3 Two vectors, of magnitudes 20 mm and 50 mm, are added together. Which one of the following is a possible value for the magnitude of the resultant?
| back 3
|
front 4 The magnitude of the resultant of two vectors cannot be less than the magnitude of either of those two vectors.
| back 4
|
front 5 If + = and their magnitudes are given by A + B = C, then the vectors and are oriented
| back 5
|
front 6 If - = 0, then the vectors and have equal magnitudes and are directed in the same direction.
| back 6
|
front 7 If three vectors add to zero, they must all have equal magnitudes.
| back 7
|
front 8 The sum of two vectors of fixed magnitudes has the greatest magnitude when the angle between these two vectors is
| back 8
|
front 9 The sum of two vectors of fixed magnitudes has its minimum magnitude when the angle between these vectors is
| back 9
|
front 10 Vectors and obey the equation + = 0. These vectors satisfy which one of the following statements?
| back 10
|
front 11 If a vector's components are all negative, then the magnitude of the vector is negative.
| back 11
|
front 12 The magnitude of a vector can never be less than the magnitude of any of its components.
| back 12
|
front 13 The magnitude of a vector an only zero if all of its components are zero.
| back 13
|
front 14 If a vector has components Ax < 0, and Ay > 0, then the angle that this vector makes with the positive x-axis must be in the range
| back 14
|
front 15 If a vector has components Ax < 0, and Ay < 0, then the angle that this vector makes with the positive x-axis must be in the range
| back 15
|
front 16 If a vector has components Ax > 0, and Ay < 0, then the angle that this vector makes with the positive x-axis must be in the range
| back 16
|
front 17 The eastward component of vector is equal to the westward component of vector and their northward components are equal. Which one of the following statements must be correct for these two vectors?
| back 17
|
front 18 Vector A is along the +x-axis and vector B is along the +y-axis. Which one of the following statements is correct with respect to these vectors?
| back 18
|
front 19 A boulder rolls off of a very high cliff and experiences no significant air resistance. While it is falling, its trajectory is never truly vertical.
| back 19
|
front 20 For general projectile motion with no air resistance, the horizontal component of a projectile's velocity
| back 20
|
front 21 For general projectile motion with no air resistance, the horizontal component of a projectile's acceleration
| back 21
|
front 22 For general projectile motion with no air resistance, the vertical component of a projectile's acceleration
| back 22
|
front 23 Which of the following statements are true about an object in two-dimensional projectile motion with no air resistance? (There could be more than one correct choice.)
| back 23
|
front 24 A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically. Which object is traveling faster when it hits the level ground below if neither of them experiences any air resistance?
| back 24
|
front 25 In an air-free chamber, a pebble is thrown horizontally, and at the same instant a second pebble is dropped from the same height. Compare the times of fall of the two pebbles.
| back 25
|
front 26 A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will
| back 26
|
front 27 James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. If there is no air resistance, when they reach the lake below
| back 27
|
front 28 James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below if there is no air resistance.
| back 28
|
front 29 A player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory
| back 29
|
front 30 A rock is thrown from the upper edge of a tall cliff at some angle above the horizontal. It reaches its highest point and starts falling down. Which of the following statements about the rock's motion are true just before it hits the ground? (There could be more than one correct choice.)
| back 30
|
front 31 If a satellite moves with constant speed in a perfectly circular orbit around the earth, what is the direction of the acceleration of the satellite?
| back 31
|
front 32 An object moves in a circular path at a constant speed. Compare the direction of the object's velocity and acceleration vectors.
| back 32
|
front 33 The Moon is accelerated toward the earth, so it is gradually getting closer to the earth.
| back 33
|
front 34 You are trying to cross a river that flows toward the south with a strong current. You start out in your motorboat on the east bank desiring to reach the west bank directly west from your starting point. You should head your motorboat
| back 34
|
front 35 The x component of vector A is 8.7 units, and its y component is -6.5 units. The magnitude of A is closest to
| back 35
|
front 36 When rolled down a mountainside at 7.0 m/s, the horizontal component of its velocity vector was 1.8 m/s. What was the angle of the mountain surface above the horizontal?
| back 36
|
front 37 When Jeff ran up a hill at 7.0 m/s, the horizontal component of his velocity vector was 5.1 m/s. What was the vertical component of Jeff's velocity?
| back 37
|
front 38 The x component of vector A is 5.3 units, and its y component is -2.3 units. The angle that vector A makes with the +x-axis is closest to
| back 38
|
front 39 A player throws a football 50.0 m at 61.0° north of west. What is the westward component of the displacement of the football?
| back 39
|
front 40 A boy jumps with a velocity of magnitude 20.0 m/s at an angle of 25.0° above the horizontal. What is the horizontal component of the boy's velocity?
| back 40
|
front 41 The magnitude of A is 5.5 m, and this vector lies in the second quadrant and makes an angle of 34 ° with the +y-axis. The components of A are closest to:
| back 41
|
front 42 A car travels 20 km west and then 20 km south. What is the magnitude of its displacement vector?
| back 42
|
front 43 You walk to the north, then turn 60° to your right and walk another How far are you from where you originally started?
| back 43
|
front 44 You walk 53 m to the north, then you turn 60° to your right and walk another Determine the direction of your displacement vector. Express your answer as an angle relative to east.
| back 44
|
front 45 If vector A has components Ax = -3.0 lb and Ay = -4.0 lb, and vector has components Bx = 3.0 lb and By = -8.0 lb, what is the magnitude of vector C = A - B?
| back 45
|
front 46 Vector A has magnitude 2 units and is directed to the north. Vector B has magnitude and is directed to the south. Calculate the magnitude and direction of A-B
| back 46
|
front 47 Two perpendicular vectors, A and B, are added together giving vector C. If the magnitudes of both vectors and are doubled without changing their directions, the magnitude of vector C will
| back 47
|
front 48 Vector M= 4.00 m points eastward and vector N= 3.00 m points southward. The resultant vector M+N is given by
| back 48
|
front 49 Vector A has a magnitude of 6.0 m and points 30° north of east. Vector B has a magnitude of 4.0 m and points 30° east of north. The resultant vector A+B is given by
| back 49
|
front 50 Vector A has a magnitude of 6.0 m and points 30° north of east. Vector B has a magnitude of 4.0 m and points 30° west of north. The resultant vector A+ B is given by
| back 50
|
front 51 Vector A has a magnitude of 6.0 m and points 30° north of east. Vector B has a magnitude of 4.0 m and points 30° west of south. The resultant vector A+B is given by
| back 51
|
front 52 Vector A has a magnitude of 6.0 m and points 30° south of east. Vector B has a magnitude of 4.0 m and points 30° west of south. The resultant vector A+B is given by
| back 52
|
front 53 An airplane undergoes the following displacements, all at the same altitude: First, it flies in a direction 30.0° east of north. Next, it flies due south. Finally, it flies 30.0° north of west. Use components to determine how far the airplane ends up from its starting point.
| back 53
|
front 54 Three forces, 1, 2, and 3, each of magnitude 70 N, all act on an object as shown in the figure. The magnitude of the resultant force acting on the object is
| back 54
|
front 55 The figure shows four vectors, A, B, C, and d, having magnitudes 12.0 m, 10.0 m, 8.0 m, and 4.0 m, respectively. The sum of these four vectors is
| back 55
|
front 56 A ball is thrown with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If we can neglect air resistance, what is the horizontal component of its instantaneous velocity at the exact top of its trajectory?
| back 56
|
front 57 A ball is thrown at an original speed of 8.0 m/s at an angle of 35° above the horizontal. If there is no air resistance, what is the speed of the ball when it returns to the same horizontal level?
| back 57
|
front 58 A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stopwatch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What is the height of the cliff if air resistance is negligibly small?
| back 58
|
front 59 A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water, assuming negligible air resistance?
| back 59
|
front 60 A ball thrown horizontally from a point 24 m above the ground, strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown, assuming negligible air resistance?
| back 60
|
front 61 The acceleration due to gravity on the Moon is only one-sixth of that on Earth, and the Moon has no atmosphere. If you hit a baseball on the Moon with the same effort (and therefore at the speed and angle) as on Earth, how far would the ball would travel on the Moon compared to on Earth? Neglect air resistance on Earth.
| back 61
|
front 62 A boy throws a rock with an initial velocity of at 30.0° above the horizontal. How long does it take for the rock to reach the maximum height of its trajectory if air resistance is negligibly small and g = 9.80 m/s2?
| back 62
|
front 63 A cat leaps to try to catch a bird. If the cat's jump was at 60° off the ground and its initial velocity was what is the highest point of its trajectory, neglecting air resistance?
| back 63
|
front 64 A fisherman casts his bait toward the river at an angle of 25° above the horizontal. As the line unravels, he notices that the bait and hook reach a maximum height of What was the initial velocity he launched the bait with? Assume that the line exerts no appreciable drag force on the bait and hook and that air resistance is negligible.
| back 64
|
front 65 A football kicker is attempting a field goal from out. The ball is kicked and just clears the lower bar with a time of flight of If the angle of the kick was 45°, what was the initial speed of the ball, assuming no air resistance?
| back 65
|
front 66 You throw a rock horizontally off a cliff with a speed of 20 m/s and no significant air resistance. After 2.0 s, the magnitude of the velocity of the rock is closest to
| back 66
|
front 67 A hockey puck slides off the edge of a platform with an initial velocity of 20 m/s horizontally. The height of the platform above the ground is 2.0 m. What is the magnitude of the velocity of the puck just before it touches the ground? You can neglect air resistance.
| back 67
|
front 68 A hockey puck slides off the edge of a horizontal platform with an initial velocity of 20 m/s horizontally and experiences no significant air resistance. The height of the platform above the ground is 2.0 m. What is the magnitude of the vertical component of the velocity of the puck just before it hits the ground?
| back 68
|
front 69 A hockey puck slides off the edge of a horizontal platform with an initial velocity of 28.0 m/shorizontally in a city where the acceleration due to gravity is 9.81 m/s2. The puck experiences no significant air resistance as it falls. The height of the platform above the ground is 2.00 m. What is the angle below the horizontal of the velocity of the puck just before it hits the ground?
| back 69
|
front 70 A plane flying horizontally at a speed of 50 m/s and at an elevation of 160 m drops a package, and 2.0 s later it drops a second package. How far apart will the two packages land on the ground if air resistance is negligible?
| back 70
|
front 71 In a room where g = 9.81 m/s2, a hockey puck slides off the edge of a platform with an initial velocity of 28.0 m/s horizontally. The height of the platform above the ground is 2.00 m. What is the speed of the puck just before it hits the ground? The air resistance is negligibly small.
| back 71
|
front 72 A ball rolls over the edge of a platform with only a horizontal velocity. The height of the platform is 1.6 m and the horizontal range of the ball from the base of the platform is 20 m. What is the horizontal velocity of the ball just before it touches the ground? Neglect air resistance.
| back 72
|
front 73 A person throws a ball horizontally from the top of a building that is 24.0 m above the ground level. The ball lands 100 m down range from the base of the building. What was the initial velocity of the ball? Neglect air resistance and use g = 9.81 m/s2.
| back 73
|
front 74 A wind farm generator uses a two-bladed propeller mounted on a pylon at a height of 20 m, as shown in the figure. The width of the pylon is very narrow, and the length of each propeller blade is 12 m. A tip of the propeller breaks off just when the propeller is vertical. The fragment flies off horizontally, falls, and strikes the ground at point P with negligible air resistance. Just before the fragment broke off, the propeller was turning uniformly, taking 1.2 s for each rotation. How far is point P from the base of the pylon?
| back 74
|
front 75 A boy throws a ball with an initial velocity of 25 m/s at an angle of 30° above the horizontal. If air resistance is negligible, how high above the projection point is the ball after 2.0 s?
| back 75
|
front 76 A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s2. What is the horizontal component of its velocity after 4.0 s?
| back 76
|
front 77 A high-speed dart is shot from ground level with a speed of 150 m/s at an angle 30° above the horizontal. What is the vertical component of its velocity after 4.0 s if air resistance is neglected?
| back 77
|
front 78 A child is trying to throw a ball over a fence. She gives the ball an initial speed of 8.0 m/s at an angle of 40° above the horizontal. The ball leaves her hand 1.0 m above the ground and the fence is 2.0 m high. The ball just clears the fence while still traveling upwards and experiences no significant air resistance. How far is the child from the fence?
| back 78
|
front 79 A boy kicks a football from ground level with an initial velocity of 20 m/s at an angle of 30° above the horizontal. What is the horizontal distance to the point where the football hits the ground if we neglect air resistance?
| back 79
|
front 80 An athlete competing in the long jump leaves the ground with a speed of 9.14 m/s at an angle of 55° with the vertical. What is the length of the athlete's jump if air resistance is of no significance?
| back 80
|
front 81 An athlete competing in the long jump leaves the ground with a speed of 9.14 m/s at an angle of 35° above the horizontal. How long does the athlete stay in the air, assuming no significant air resistance?
| back 81
|
front 82 An athlete participates in an interplanetary discus throw competition during an Olympiad that takes place on a planet where the acceleration due to gravity is 9.7 m/s2. He throws the discus with an initial velocity of 20 m/s at an angle of 60° from the vertical. Neglecting air resistance and the height of the discus at the point of release, what is the range of the discus?
| back 82
|
front 83 A child throws a ball with an initial speed of 8.0 m/s at an angle of 40° above the horizontal. The ball leaves her hand 1.0 m above the ground. At what angle below the horizontal does the ball approach the ground?
| back 83
|
front 84 The horizontal and vertical components of the initial velocity of a football are 16 m/s and 20 m/s respectively. If there is no air resistance, how long does it take the football to reach the top of its trajectory?
| back 84
|
front 85 A projectile is fired at an angle above the horizontal at a location where g = 9.8 m/s2. The initial x and y components of its velocity are 86.6 m/s and 50 m/s respectively. At what angle was the projectile fired above the horizontal?
| back 85
|
front 86 A projectile is fired from ground level at an angle above the horizontal on an airless planet where g = 10.0 m/s2. The initial x and y components of its velocity are 86.6 m/s and 50.0 m/s respectively. How long after firing does it take before the projectile hits the level ground?
| back 86
|
front 87 A projectile is launched with an initial velocity of 80 m/s at 30° above the horizontal. Neglecting air resistance, what is horizontal component of the projectile's acceleration?
| back 87
|
front 88 A boy kicks a football with an initial velocity of 20 m/s at an angle of 25° above the horizontal. If we neglect air resistance, the magnitude of the acceleration of the ball while it is in flight is
| back 88
|