Q&A Hero

Q: A Ferris wheel with a radius of 8.0m makes 1 revolution every 10 s. When he is at the top, essentially a diameter above the ground, he releases a ball. How far from the point on the ground directly under the release point does the ball land? A) 0 m B) 1.0 m C) 8.0 m D) 9.1 m E) 16 m

Q: A stone is tied to the end of a string and is swung with constant speed around a horizontal circle with a radius of 1.5 m. If it makes two complete revolutions each second, its acceleration is: A) 0.24 m/s2 B) 2.4 m/s2 C) 24 m/s2 D) 240 m/s2 E) 2400 m/s2

Q: A girl jogs around a horizontal circle with a constant speed. She travels one fourth of a revolution, a distance of 25 m along the circumference of the circle, in 5.0 s. The magnitude of her acceleration is: A) 0.31 m/s2 B) 1.3 m/s2 C) 1.6 m/s2 D) 3.9 m/s2 E) 6.3 m/s2

Q: For a biological sample in a 1.0-m radius centrifuge to have a centripetal acceleration of 25g its speed must be: A) 11 m/s B) 16 m/s C) 50 m/s D) 122 m/s E) 245 m/s

Q: A car rounds a 20-m radius curve at a speed of 10 m/s. The magnitude of its acceleration is: A) 0 m/s2 B) 0.20 m/s2 C) 5.0 m/s2 D) 40 m/s2 E) 400 m/s2

Q: A stone is tied to a 0.50-m string and whirled at a constant speed of 4.0 m/s in a vertical circle. The acceleration at the bottom of the circle is: A) 9.8 m/s2, up B) 9.8 m/s2, down C) 8.0 m/s2, up D) 32 m/s2, up E) 32 m/s2, down

Q: A stone is tied to a 0.50-m string and whirled at a constant speed of 4.0 m/s in a vertical circle. Its acceleration at the top of the circle is: A) 9.8 m/s2, up B) 9.8 m/s2, down C) 8.0 m/s2, down D) 32 m/s2, up E) 32 m/s2, down

Q: Two objects are traveling around different circular orbits with constant speed. They both have the same acceleration but object A is traveling twice as fast as object B. The orbit radius for object A is _______ the orbit radius for object B. A) one-fourth B) one-half C) the same as D) twice E) four times

Q: A stone is tied to a string and whirled at constant speed in a horizontal circle. The speed is then doubled without changing the length of the string. Afterward the magnitude of the acceleration of the stone is: A) the same B) twice as great C) four times as great D) half as great E) one-fourth as great

Q: An object is moving on a circular path of radius meters at a constant speed of 4.0 m/s. The time required for one revolution is:A) 2/2sB) 2/2 sC) /2 sD) 2/4 sE) 2/s

Q: An airplane is flying north at 500 km/h. It makes a gradual 180°turn at constant speed, changing its direction of travel from north through east to south. The process takes 40 s. The average acceleration of the plane for this turn is:A) 12.5 km/h.s, northB) 12.5 km/h.s, eastC) 12.5 km/h.s, southD) 25 km/h.s, northE) 25 km/h.s, south

Q: An airplane makes a gradual 90ï‚°turn while flying at a constant speed of 200 m/s. The process takes 20.0 seconds to complete. For this turn the magnitude of the average acceleration of the plane is: A) 0 m/s2 B) 40 m/s2 C) 20 m/s2 D) 14 m/s2 E) 10 m/s2

Q: A particle moves at constant speed in a circular path. The instantaneous velocity and instantaneous acceleration vectors are: A) both tangent to the circular path B) both perpendicular to the circular path C) perpendicular to each other D) opposite to each other E) none of the above

Q: A toy racing car moves with constant speed around the circle shown below. When it is at point A its coordinates are x= 0, y= 3m and its velocity is (6 m/s). When it is at point B its velocity and acceleration are:A) -(6 m/s) and (12 m/s2), respectivelyB) (6 m/s) and -(12 m/s2), respectivelyC) (6 m/s) and (12 m/s2), respectivelyD) (6 m/s) and (12 m/s2), respectivelyE) (6 m/s) and 0 m/s2, respectively

Q: An object, tied to a string, moves in a circle at constant speed on a horizontal surface as shown. The direction of the displacement of this object, as it travels from W to X is:

Q: A ball is thrown horizontally from the top of a 20-m high hill. It strikes the ground at an angle of 45ï‚°. With what speed was it thrown? Use g= 10 m/s2. A) 14 m/s B) 20 m/s C) 28 m/s D) 32 m/s E) 40 m/s

Q: Two projectiles are in flight at the same time. The acceleration of one relative to the other: A) is always 9.8 m/s2 B) can be as large as 19.6 m/s2 C) can be horizontal D) is zero E) none of these

Q: A stone thrown from the top of a tall building follows a path that is: A) circular B) made of two straight line segments C) hyperbolic D) parabolic E) a straight line

Q: A projectile is fired over level ground with an initial velocity that has a vertical component of 20 m/s and a horizontal component of 30 m/s. Using g= 10 m/s2, the distance from launching to landing points is: A) 40 m B) 60 m C) 80 m D) 120 m E) 180 m

Q: A dart is thrown horizontally toward X at 20 m/s as shown. It hits Y 0.1 s later. The distance XY is: A) 2 m B) 1 m C) 0.5 m D) 0.1 m E) 0.05 m

Q: A cannon fires a projectile as shown. The dashed line shows the trajectory in the absence of gravity; points MNOP correspond to the position of the projectile at one second intervals. If g= 10 m/s2, the lengths X,Y,Z are: A) 5 m, 10 m, 15 m B) 5 m, 20 m, 45 m C) 10 m, 40 m, 90 m D) 10 m, 20 m, 30 m E) 0.2 m, 0.8 m, 1.8 m

Q: A boy on the edge of a vertical cliff 20 m high throws a stone horizontally outwards with a speed of 20 m/s. It strikes the ground at what horizontal distance from the foot of the cliff? Use g= 10 m/s2 A) 10 m B) 40 m C) 50 m D) 50 m E) none of these

Q: A large cannon is fired from ground level over level ground at an angle of 30ï‚°above the horizontal. The muzzle speed is 980 m/s. Neglecting air resistance, the projectile will travel what horizontal distance before striking the ground? A) 4.3 km B) 8.5 km C) 43 km D) 85 km E) 170 km

Q: A stone is thrown outward from the top of a 59.4-m high cliff with an upward velocity component of 19.5 m/s. How long is the stone in the air? Assume that it lands on the ground below the cliff, and that the ground below the cliff is flat. A) 4.00 s B) 5.00 s C) 6.00 s D) 7.00 s E) 8.00 s

Q: An object is shot from the back of a railroad flatcar moving at 40 km/h on a straight horizontal road. The launcher is aimed upward, perpendicular to the bed of the flatcar. The object falls: A) in front of the flatcar B) behind the flatcar C) on the flatcar D) either behind or in front of the flatcar, depending on the initial speed of the object E) to the side of the flatcar

Q: The airplane shown is in level flight at an altitude of 0.50 km and a speed of 150 km/h. At what distance d should it release a heavy bomb to hit the target X? Take g= 10 m/s2. A) 150 m B) 295 m C) 417 m D) 1500 m E) 15,000 m

Q: A bomber flying in level flight with constant velocity drops a bomb before it is over the target. Neglecting air resistance, which one of the following is NOT true? A) The bomber is over the target when the bomb strikes B) The acceleration of the bomb is constant C) The horizontal velocity of the plane equals the vertical velocity of the bomb when it hits the target D) The bomb travels in a curved path E) The time of flight of the bomb is independent of the horizontal speed of the plane

Q: A bullet shot horizontally from a gun: A) strikes the ground much later than one dropped vertically from the same point at the same instant B) never strikes the ground C) strikes the ground at approximately the same time as one dropped vertically from the same point at the same instant D) travels in a straight line E) strikes the ground much sooner than one dropped from the same point at the same instant

Q: Which of the curves on the graph below best represents the vertical component vyversus tfor a projectile fired at an angle of 45ï‚°above the horizontal? A) OC B) DE C) AB D) AE E) AF

Q: A stone is thrown horizontally and follows the path XYZ shown. The direction of the acceleration of the stone at point Y is: A)  B)  C) D) E)

Q: Identical guns fire identical bullets horizontally at the same speed from the same height above level planes, one on the Earth and one on the Moon. Which of the following three statements is/are true? I. The horizontal distance traveled by the bullet is greater for the Moon. II. The flight time is less for the bullet on the Earth. III. The velocities of the bullets at impact are the same. A) III only B) I and II only C) I and III only D) II and III only E) I, II, III

Q: The velocity of a projectile equals its initial velocity added to: A) a constant horizontal velocity B) a constant vertical velocity C) a constantly increasing horizontal velocity D) a constantly increasing downward velocity E) a constant velocity directed at the target

Q: Two bodies are falling with negligible air resistance, side by side, above a horizontal plane. If one of the bodies is given an additional horizontal acceleration during its descent, it: A) strikes the plane at the same time as the other body B) strike the plane earlier than the other body C) has the vertical component of its velocity altered D) has the vertical component of its acceleration altered E) follows a straight line path along the resultant acceleration vector

Q: An object is at rest at x= 0 m, y= 0 m. It accelerates at a rate of (-3.2 m/s2) + (8.6 m/s2). After accelerating for 4.7 seconds its coordinates are:A) x= -15 m, y= 40 mB) x= -35 m, y= 95 mC) x= -24 m, y= 170 mD) x= -70 m, y= 190 mE) x= -48 m, y= 340 m

Q: The velocity of an object as a function of time is given by v= (12.5t-7.2t2) + (4.3t3). What is its acceleration as a function of time?A) a= (12.5 -14.4t) + (12.9t2)B) a= (-7.2) + (4.3t)C) a= (5.3t) + (12.9t2)D) a= (-7.2) + (8.6t)E) a= (-14.4t) + (4.3t2)

Q: An object has a velocity of (5.4 m/s) - (4.8 m/s). Over a period of 1.3 s, its velocity changes to (1.7 m/s) + (5.9 m/s). What is its acceleration?A) -(3.7 m/s) + (11 m/s)B) -(2.8 m/s) + (8.2 m/s)C) (3.7 m/s) + (11 m/s)D) (2.8 m/s) + (8.2 m/s)E) -(2.8 m/s) + (1.1 m/s)

Q: Which of the following is NOT an example of accelerated motion? A) Vertical component of projectile motion B) Circular motion at constant speed C) A swinging pendulum D) Earth's motion about sun E) Horizontal component of projectile motion

Q: Acceleration is defined as: A) rate of change of position with time B) speed divided by time C) rate of change of velocity with time D) a speeding up or slowing down E) change of velocity

Q: A plane traveling north at 200 m/s turns and then travels south at 200 m/s. The change in its velocity is: A) 0 m/s B) 200 m/s north C) 200 m/s south D) 400 m/s north E) 400 m/s south

Q: The position of an object as a function of time is given in meters by x= (at+bt2) + (ct). What is its velocity as a function of time? A) v= (a +b) + (c) B) v= (a +2b) + (c) C) v= (a +2bt) + (c) D) v= b E) v= 2b

Q: An object moves from x= -2.1 m, y= 3.7 m to x= 3.3 m, y= -1.1 m in a time of 5.3 s. What is its average velocity?A) 7.2 m/s, 32 below the positive x-axisB) 2.5 m/s, 48 below the positive x-axisC) 1.4 m/s, 42 below the positive x-axisD) 4.9 m/s, 76 below the positive x-axisE) 0.92 m/s, 14 below the positive x-axis

Q: An object moves from x= -2.1 m, y= 3.7 m, z= 1.4 m to x= 3.3 m, y= -1.1 m, z= 4.2 m in a time of 5.3 s. What is its average velocity?A) (0.23 m/s) + (0.49 m/s) + (0.53 m/s)B) (5.4 m/s) - (4.8 m/s) + (2.8 m/s)C) (1.0 m/s) - (0.91 m/s) + (0.53 m/s)D) (1.0 m/s) + (0.91 m/s) + (1.1 m/s)E) -(1.0 m/s) + (0.91 m/s) + (0.53 m/s)

Q: What is the difference between speed and velocity? A) Speed is the magnitude of velocity; velocity is a vector and has both magnitude and direction. B) There is no difference. C) Speed is the rate at which something moves, while velocity is the direction in which it moves. D) Speed is used when describing motion in one dimension, while velocity is used when describing motion in two dimensions. E) Speed is the rate at which velocity changes.

Q: A jet plane in straight horizontal flight passes over your head. When it is directly above you, the sound seems to come from a point behind the plane in a direction 30ï‚°from the vertical. The speed of the plane is: A) the same as the speed of sound B) half the speed of sound C) three-fifths the speed of sound D) 0.866 times the speed of sound E) twice the speed of sound

Q: A particle goes from x= -2 m, y= 3 m, z= 1 m to x= 3 m, y= -1 m, z= 4 m. Its displacement is:A) (1 m) + (2 m) + (5 m)B) (5 m) - (4 m) + (3 m)C) -(5 m) + (4 m) - (3 m)D) -(1 m) - (2 m) - (5 m)E) -(5 m) - (2 m) - (3 m)

Q: From your window you can see a high-rise building several blocks away. You check the map and see that the building is 560 m away from you in a straight line, in a direction 30 south of east. However, the roads are all east-west and north-south. If you want to walk from your house to the building, how far in each direction do you have to walk? A) 480 m east and 280 m south B) 280 m east and 480 m south C) 280 m east and 280 m south D) 480 m east and 50 m south E) cannot be determined without looking at the streets on the map

Q: Sally starts from home, walks 300 m east and then 500 m south, and arrives at her school. How far, in a straight line, is Sally's school from her home? A) 300 m B) 500 m C) 580 m D) 640 m E) 800 m

Q: Which of the following is a vector quantity? A) Mass B) Density C) Speed D) Temperature E) None of these

Q: Velocity is defined as: A) rate of change of position with time B) position divided by time C) rate of change of acceleration with time D) a speeding up or slowing down E) change of position

Q: Which of the following is a scalar quantity? A) Speed B) Velocity C) Displacement D) Acceleration E) None of these

Q: The result of is: A) 0 B) +1 C) D) E)

Q: The value of is:A) 0B) +1C) -1D) 3E)

Q: The value of is:A) 0B) +1C) -1D) 3E)

Q: The value of is:A) 0B) +1C) -1D) 3E)

Q: Let and 90°, where is the angle between and when they are drawn with their tails at the same point. Which of the following is NOT true?A) B) C) D) E)

Q: The two vectors (3 m) - (7 m) and (2 m) + (3 m) - (2 m) define a plane (it is the plane of the triangle with both tails at one vertex and each head at one of the other vertices). Which of the following vectors is perpendicular to the plane?A) (14 m) + (6 m) + (23 m)B) (-14 m) + (6 m) + (23 m)C) (14 m) - (6 m) + (23 m)D) (14 m) + (6 m) - (23 m)E) (14 m) + (6 m)

Q: Two vectors lie with their tails at the same point. When the angle between them is increased by 20the magnitude of their vector product doubles. The original angle between them was about:A) 0B) 18°C) 25°D) 45°E) 90°

Q: Vectors and each have magnitude L. When drawn with their tails at the same point, the angle between them is 30°. The magnitude of is:A) L2/2B) L2C) D) 2L2E) none of these

Q: If the magnitude of the sum of two vectors is greater than the magnitude of either vector, then: A) the scalar product of the vectors must be negative B) the scalar product of the vectors must be positive C) the vectors must be parallel and in opposite directions D) the vectors must be parallel and in the same direction E) none of the above

Q: If the magnitude of the sum of two vectors is less than the magnitude of either vector, then: A) the scalar product of the vectors must be negative B) the scalar product of the vectors must be positive C) the vectors must be parallel and in opposite directions D) the vectors must be parallel and in the same direction E) none of the above

Q: Two vectors have magnitudes of 10 and 15. The angle between them when they are drawn with their tails at the same point is 65ï‚°. The component of the longer vector along the line of the shorter is: A) 0 B) 4.2 C) 6.3 D) 9.1 E) 14

Q: Let = (1 m) + (2 m) + (2 m) and = (3 m) + (4 m). The angle between these two vectors is given by:A) cos-1(14/15)B) cos-1(11/225)C) cos-1(104/225)D) cos-1(11/15)E) cannot be found since and do not lie in the same plane

Q: Two vectors lie with their tails at the same point. When the angle between them is increased by 20ï‚°their scalar product has the same magnitude but changes from positive to negative. The original angle between them was:A) 0B) 60°C) 70°D) 80°E) 90°

Q: Let = (2 m) + (6 m) - (3 m) and = (4 m) + (2 m) + (1 m). Then equals:A) (8 m) + (12 m) - (3 m)B) (12 m) - (14 m) - (20 m)C) 23D) 17E) none of these

Q: Vectors and each have magnitude L. When drawn with their tails at the same point, the angle between them is 30°. The value of is:A) 0B) L2C) D) 2L2E) none of these

Q: Which of the following is correct? A) Multiplying a vector by a scalar gives a scalar result. B) Multiplying a vector by a vector always gives a vector result. C) Multiplying a vector by a vector never gives a scalar result. D) The only type of vector multiplication that gives a scalar result is the dot product. E) The only type of vector multiplication that gives a vector result is the cross product.

Q: If = (6 m) - (8 m) then has magnitude:A) -8 mB) 8 mC) 10 mD) 40 mE) 56 m

Q: A certain vector in the xyplane has an xcomponent of 4m and a ycomponent of 10m. It is then rotated in the xyplane so its xcomponent is doubled. Its new ycomponent is about: A) 20 m B) 7.2 m C) 5.0 m D) 4.5 m E) 2.2 m

Q: In the diagram, has magnitude 12 m and has magnitude 8 m. The xcomponent of is about: A) 1.5 m B) 4.5 m C) 12 m D) 15 m E) 20 m

Q: If = (2 m) - (3 m) and = (1 m) - (2 m), then =A) (1 m)B) (-1 m)C) (4 m) - (7 m)D) (4 m) + (1 m)E) (-4 m) + (7 m)

Q: Let = (2 m) + (6 m) - (3 m) and = (4 m) + (2 m) + (1 m). The vector difference is:A) (6 m) + (8 m) - (2 m)B) (-2 m) + (4 m) - (4 m)C) (2 m) - (4 m) + (4 m)D) (8 m) + (12 m) - (3 m)E) none of these

Q: Let = (2 m) + (6 m) - (3 m) and = (4 m) + (2 m) + (1 m). The vector sum is:A) (6 m) + (8 m) - (2 m)B) (-2 m) + (4 m) - (4 m)C) (2 m) - (4 m) + (4 m)D) (8 m) + (12 m) - (3 m)E) none of these

Q: The angle between = -(25 m) + (45 m)and the positive xaxis is:A) 29°B) 61°C) 119°D) 151°E) 209°

Q: The angle between = (25 m) + (45 m) and the positive xaxis is:A) 29°B) 61°C) 151°D) 209°E) 241°

Q: A vector in the xyplane has a magnitude of 25 and an xcomponent of 12. The angle it makes with the positive xaxis is:A) 26°B) 29°C) 61°D) 64°E) 241°

Q: Let . The magnitude of is: A) 5.00 B) 5.57 C) 7.00 D) 7.42 E) 8.54

Q: A vector has a component of 10 m in the +xdirection, a component of 10 m in the +ydirection, and a component of 5 m in the +zdirection. The magnitude of this vector is: A) 0 m B) 15 m C) 20 m D) 25 m E) 225 m

Q: If the xcomponent of a vector , in the xyplane, is half as large as the magnitude of the vector, the tangent of the angle between the vector and the xaxis is: A) B) 1/2 C) D) 3/2 E) 3

Q: A vector has a magnitude of 12. When its tail is at the origin it lies between the positive xaxis and negative yaxis and makes an angle of 30°with the x axis. Its ycomponent is:A) B) C) 6D) -6E) 12

Q: 30 isA) /10 radiansB) /6 radiansC) 1 radianD) /2 radiansE) radians