NY Regents June 2013, Part 3
Some questions may require the use of the 2006 Edition Reference Tables for Physical Setting/Physics.

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A 25.0-meter length of platinum wire with a cross-sectional area of 3.50 x 10-6 meter2 has a resistance of 0.757 ohm at 20°C.
 51–52. Calculate the resistivity of the wire. [Show all work, including the equation and substitution with units.]   [2]

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The diagram below represents a periodic wave moving along a rope.

 53. On the grid in your answer booklet, draw at least one full wave with the same amplitude and half the wavelength of the given wave.   [1]

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A baseball bat exerts an average force of 600. newtons east on a ball, imparting an impulse of 3.6 newton•seconds east to the ball.
 54–55. Calculate the amount of time the baseball bat is in contact with the ball. [Show all work, including the equation and substitution with units.]   [2]

 56. The diagram below shows the north pole of one bar magnet located near the south pole of another bar magnet.     On the diagram in your answer booklet, draw three magnetic field lines in the region between the magnets.  [1]

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The graph below shows the relationship between speed and elapsed time for a car moving in a straight line.

 57. Determine the magnitude of the acceleration of the car.  [1]

 58–59. Calculate the total distance the car traveled during the time interval 4.0 seconds to 8.0 seconds. [Show all work, including the equation and substitution with units.]   [2]

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A 20.-ohm resistor, R1, and a resistor of unknown resistance, R2, are connected in parallel to a 30.-volt source, as shown in the circuit diagram below. An ammeter in the circuit reads 2.0 amperes.

 60. Determine the equivalent resistance of the circuit.  [1]

 61–62. Calculate the resistance of resistor R2. [Show all work, including the equation and substitution with units.]   [2]

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A 28-gram rubber stopper is attached to a string and whirled clockwise in a horizontal circle with a radius of 0.80 meter. The diagram in your answer booklet represents the motion of the rubber stopper. The stopper maintains a constant speed of 2.5 meters per second.
 63–64. Calculate the magnitude of the centripetal acceleration of the stopper. [Show all work, including the equation and substitution with units.]  [2]

 65. On the diagram in your answer booklet, draw an arrow showing the direction of the centripetal force acting on the stopper when it is at the position shown.  [1]

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Auroras over the polar regions of Earth are caused by collisions between charged particles from the Sun and atoms in Earth’s atmosphere. The charged particles give energy to the atoms, exciting them from their lowest available energy level, the ground state, to higher energy levels, excited states. Most atoms return to their ground state within 10. nanoseconds.

In the higher regions of Earth’s atmosphere, where there are fewer interatom collisions, a few of the atoms remain in excited states for longer times. For example, oxygen atoms remain in an excited state for up to 1.0 second. These atoms account for the greenish and red glows of  the auroras.  As these oxygen atoms return to their ground state, they emit green photons (f = 5.38 x 1014 Hz) and red photons (f = 4.76 x 1014 Hz). These emissions last long enough to produce the changing aurora phenomenon.
 66.  What is the order of magnitude of the time, in seconds, that most atoms spend in an excited state?   [1]

 67–68. Calculate the energy of a photon, in joules, that accounts for the red glow of the aurora. [Show all work, including the equation and substitution with units.]  [2]

 69. Explain what is meant by an atom being in its ground state.   [1]

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A girl rides her bicycle 1.40 kilometers west, 0.70 kilometer south, and 0.30 kilometer east in 12 minutes. The vector diagram in your answer booklet represents the girl’s first two displacements in sequence from point P. The scale used in the diagram is 1.0 centimeter = 0.20 kilometer.
 70–71. On the vector diagram in your answer booklet, using a ruler and a protractor, construct the following vectors: • Starting at the arrowhead of the second displacement vector, draw a vector to represent the 0.30 kilometer east displacement. Label the vector with its magnitude.  [1] • Draw the vector representing the resultant displacement of the girl for the entire bicycle trip and label the vector R.   [1]

 72–73. Calculate the girl’s average speed for the entire bicycle trip. [Show all work, including the equation and substitution with units.]   [2]

 74.  Determine the magnitude of the girl’s resultant displacement for the entire bicycle trip, in kilometers.   [1]

 75. Determine the measure of the angle, in degrees, between the resultant and the 1.40-kilometer displacement vector.  [1]

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A light ray with a frequency of 5.09 x 1014 hertz traveling in water has an angle of incidence of 35° on a water-air interface. At the interface, part of the ray is reflected from the interface and part of the ray is refracted as it enters the air.
 76. What is the angle of reflection of the light ray at the interface?   [1]

 77. On the diagram in your answer booklet, using a protractor and a straightedge, draw the reflected ray.  [1]

 78–79. Calculate the angle of refraction of the light ray as it enters the air. [Show all work, including the equation and substitution with units.]  [2]

 80. Identify one characteristic of this light ray that is the same in both the water and the air.  [1]

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A 30.4-newton force is used to slide a 40.0-newton crate a distance of 6.00 meters at constant speed along an incline to a vertical height of 3.00 meters.

 81. Determine the total work done by the 30.4-newton force in sliding the crate along the incline.  [1]

 82–83. Calculate  the  total  increase  in  the  gravitational  potential  energy  of  the  crate after  it  has  slid 6.00 meters along the incline. [Show all work, including the equation and substitution with units.] [2]

 84. State what happens to the kinetic energy of the crate as it slides along the incline.   [1]

 85. State what happens to the internal energy of the crate as it slides along the incline.  [1]