June 2013 Physics Regents

1. Which term identifies a scalar quantity?

(1) displacement
(2) momentum
(3) velocity
(4) time

2. Two $20.$ -newton forces act concurrently on an object. What angle between these forces will produce a resultant force with the greatest magnitude?

(1) $0^{\circ}$
(2) $45^{\circ}$
(3) $90^{\circ}$
(4) $180^{\circ}$

3. A car traveling west in a straight line on a highway decreases its speed from $30.0$ meters per second to $23.0$ meters per second in $2.00$ seconds. The car’s average acceleration during this time interval is

(1) $3.5$ $m/s^{2}$ east
(2) $3.5$ $m/s^{2}$ west
(3) $13$ $m/s^{2}$ east
(4) $13$ $m/s^{2}$ west

4. In a race, a runner traveled $12$ meters in $4.0$ seconds as she accelerated uniformly from rest. The magnitude of the acceleration of the runner was

(1) $0.25$ $m/s^{2}$
(2) $1.5$ $m/s^{2}$
(3) $3.0$ $m/s^{2}$
(4) $48$ $m/s^{2}$

5. A projectile is launched at an angle above the ground. The horizontal component of the projectile’s velocity, $v_{x}$ , is initially $40.$ meters per second. The vertical component of the projectile’s velocity, $v_{y}$ , is initially $30.$ meters per second. What are the components of the projectile’s velocity after $2.0$ seconds of flight? [Neglect friction.]

(1) $v_{x} = 40.$ m/s and $v_{y} = 10.$ m/s
(2) $v_{x} = 40.$ m/s and $v_{y} = 30.$ m/s
(3) $v_{x} = 20.$ and $v_{y} = 10.$ m/s
(4) $v_{x} = 20.$ m/s and $v_{y} = 30.$ m/s

6. A ball is thrown with an initial speed of $10.$ meters per second. At what angle above the horizontal should the ball be thrown to reach the greatest height?

(1) $0^{\circ}$
(2) $30^{\circ}$
(3) $45^{\circ}$
(4) $90^{\circ}$

7. Which object has the greatest inertia?

(1) a $0.010$ -kg bullet traveling at $90.$ m/s
(2) a $30.$ -kg child traveling at $10.$ m/s on her bike
(3) a $490$ -kg elephant walking with a speed of $1.0$ m/s
(4) a $1500$ -kg car at rest in a parking lot

8. An $8.0$ -newton wooden block slides across a horizontal wooden floor at constant velocity. What is the magnitude of the force of kinetic friction between the block and the floor?

(1) $2.4$ N
(2) $3.4$ N
(3) $8.0$ N
(4) $27$ N

9. Which situation represents a person in equilibrium?

(1) a child gaining speed while sliding down a slide
(2) a woman accelerating upward in an elevator
(3) a man standing still on a bathroom scale
(4) a teenager driving around a corner in his car

10. A rock is thrown straight up into the air. At the highest point of the rock’s path, the magnitude of the net force acting on the rock is

(1) less than the magnitude of the rock’s weight, but greater than zero
(2) greater than the magnitude of the rock’s weight
(3) the same as the magnitude of the rock’s weight
(4) zero

11. The diagram below shows a compressed spring between two carts initially at rest on a horizontal, frictionless surface. Cart $A$ has a mass of $2$ kilograms and cart $B$ has a mass of $1$ kilogram. A string holds the carts together.

The string is cut and the carts move apart. Compared to the magnitude of the force the spring exerts on cart $A$ , the magnitude of the force the spring exerts on cart $B$ is

(1) the same
(2) half as great
(3) twice as great
(4) four times as great

12. An $8.0$ -newton block is accelerating down a frictionless ramp inclined at $15^{\circ}$ to the horizontal, as shown in the diagram below.

What is the magnitude of the net force causing the block’s acceleration?

(1) $0$ N
(2) $2.1$ N
(3) $7.7$ N
(4) $8.0$ N

13. At a certain location, a gravitational force with a magnitude of $350$ newtons acts on a $70.$ -kilogram astronaut. What is the magnitude of the gravitational field strength at this location?

(1) $0.20$ kg/N
(2) $5.0$ N/kg
(3) $9.8$ m/s²
(4) $25 000$ N $\bullet$ kg

14. A spring gains $2.34$ joules of elastic potential energy as it is compressed $0.250$ meter from its equilibrium position. What is the spring constant of this spring?

(1) $9.36$ N/m
(2) $18.7$ N/m
(3) $37.4$ N/m
(4) $74.9$ N/m

15. When a teacher shines light on a photocell attached to a fan, the blades of the fan turn. The brighter the light shone on the photocell, the faster the blades turn. Which energy conversion is illustrated by this demonstration?

(1) light $\rightarrow$ thermal $\rightarrow$ mechanical
(2) light $\rightarrow$ nuclear $\rightarrow$ thermal
(3) light $\rightarrow$ electrical $\rightarrow$ mechanical
(4) light $\rightarrow$ mechanical $\rightarrow$ chemical

16. Which statement describes a characteristic common to all electromagnetic waves and mechanical waves?

(1) Both types of waves travel at the same speed.
(2) Both types of waves require a material medium for propagation.
(3) Both types of waves propagate in a vacuum.
(4) Both types of waves transfer energy.

17. An electromagnetic wave is produced by charged particles vibrating at a rate of $3.9 \times 10^{8}$ vibrations per second. The electromagnetic wave is classified as

(1) a radio wave
(2) an infrared wave
(3) an x-ray
(4) visible light

18. The energy of a sound wave is most closely related to the wave’s

(1) frequency
(2) amplitude
(3) wavelength
(4) speed

19. A sound wave traveling eastward through the air causes the air molecules to

(1) vibrate east and west
(2) vibrate north and south
(3) move eastward, only
(4) move northward, only

20. What is the speed of light ( $f = 5.09 \times 10^{14}$ Hz) in ethyl alcohol?

(1) $4.53 \times 10^{-9}$ m/s
(2) $2.43 \times 10^{2}$ m/s
(3) $1.24 \times 10^{8}$ m/s
(4) $2.21 \times 10^{8}$

21. In the diagram below, an ideal pendulum released from position $A$ swings freely to position $B$ .

As the pendulum swings from $A$ to $B$ , its total mechanical energy

(1) decreases, then increases
(2) increases, only
(3) increases, then decreases
(4) remains the same

22. The diagram below represents a periodic wave.

Which two points on the wave are out of phase?

(1) $A$ and $C$
(2) $B$ and $F$
(3) $C$ and $E$
(4) $D$ and $G$

23. A dry plastic rod is rubbed with a wool cloth and then held near a thin stream of water from a faucet. The path of the stream of water is changed, as represented in the diagram below.

Which force causes the path of the stream of water to change due to the plastic rod?

(1) nuclear
(2) magnetic
(3) electrostatic
(4) gravitational

24. A distance of $1.0 \times 10^{-2}$ meter separates successive crests of a periodic wave produced in a shallow tank of water. If a crest passes a point in the tank every $4.0 \times 10^{-1}$ second, what is the speed of this wave?

(1) $2.5 \times 10^{-4}$ m/s
(2) $4.0 \times 10^{-3}$ m/s
(3) $2.5 \times 10^{-2}$ m/s
(4) $4.0 \times 10^{-1}$ m/s

25. One vibrating $256$ -hertz tuning fork transfers energy to another $256$ -hertz tuning fork, causing the second tuning fork to vibrate. This phenomenon is an example of

(1) diffraction
(2) reflection
(3) refraction
(4) resonance

26. Sound waves are produced by the horn of a truck that is approaching a stationary observer. Compared to the sound waves detected by the driver of the truck, the sound waves detected by the observer have a greater

(1) wavelength
(2) frequency
(3) period
(4) speed

27. An electronvolt is a unit of

(1) energy
(2) charge
(3) electric field strength
(4) electric potential difference

28. Which particle would produce a magnetic field?

(1) a neutral particle moving in a straight line
(2) a neutral particle moving in a circle
(3) a stationary charged particle
(4) a moving charged particle

29. A physics student takes her pulse and determines that her heart beats periodically $60$ times in $60$ seconds. The period of her heartbeat is

(1) $1$ Hz
(2) $60$ Hz
(3) $1$ s
(4) $60$ s

30. Moving $4.0$ coulombs of charge through a circuit requires $48$ joules of electric energy. What is the potential difference across this circuit?

(1) $190$ V
(2) $48$ V
(3) $12$ V
(4) $4.0$ V

31. The diagram below shows currents in a segment of an electric circuit.

What is the reading of ammeter $A$ ?

(1) $1$ A
(2) $5$ A
(3) $9$ A
(4) $15$ A

32. An electric dryer consumes $6.0 \times 10^{6}$ joules of electrical energy when operating at $220$ volts for $1.8 \times 10^{3}$ seconds. During operation, the dryer draws a current of

(1) $10.$ A
(2) $15$ A
(3) $9.0 \times 10^{2}$ A
(4) $3.3 \times 10^{3}$ A

33. Which net charge could be found on an object?

(1) $+4.80 \times 10^{-19}$ C
(2) $+2.40 \times 10^{-19}$ C
(3) $-2.40 \times 10^{-19}$ C
(4) $-5.60 \times 10^{-19}$ C

34. A photon is emitted as the electron in a hydrogen atom drops from the $n = 5$ energy level directly to the $n = 3$ energy level. What is the energy of the emitted photon?

(1) $0.85$ eV
(2) $0.97$ eV
(3) $1.51$ eV
(4) $2.05$ eV

35. In a process called pair production, an energetic gamma ray is converted into an electron and a positron. It is not possible for a gamma ray to be converted into two electrons because

(1) charge must be conserved
(2) momentum must be conserved
(3) mass-energy must be conserved
(4) baryon number must be conserved

36. The approximate length of an unsharpened No. $2$ pencil is

(1) $2.0 \times 10^{-2}$ m
(2) $2.0 \times 10^{-1}$ m
(3) $2.0 \times 10^{0}$ m
(4) $2.0 \times 10^{1}$ m

37. The diagram below shows an $8.0$ -kilogram cart moving to the right at $4.0$ meters per second about to make a head-on collision with a $4.0$ -kilogram cart moving to the left at $6.0$ meters per second.

After the collision, the $4.0$ -kilogram cart moves to the right at $3.0$ meters per second. What is the velocity of the $8.0$ -kilogram cart after the collision?

(1) $0.50$ m/s left
(2) $0.50$ m/s right
(3) $5.5$ m/s left
(4) $5.5$ m/s right

38. Four forces act concurrently on a block on a horizontal surface as shown in the diagram below.

As a result of these forces, the block

(1) moves at a constant speed to the right
(2) moves at a constant speed to the left
(3) accelerates to the right
(4) accelerates to the left

39. If a motor lifts a $400.$ -kilogram mass a vertical distance of $10.$ meters in $8.0$ seconds, the minimum power generated by the motor is

(1) $3.2 \times 10^{2}$ W
(2) $5.0 \times 10^{2}$ W
(3) $4.9 \times 10^{3}$ W
(4) $3.2 \times 10^{4}$ W

40. A $4.0$ -kilogram object is accelerated at $3.0$ meters per second² north by an unbalanced force. The same unbalanced force acting on a $2.0$ -kilogram object will accelerate this object toward the north at

(1) $12$ $m/s^{2}$
(2) $6.0$ $m/s^{2}$
(3) $3.0$ $m/s^{2}$
(4) $1.5$ $m/s^{2}$

41. An electron is located in an electric field of magnitude $600.$ newtons per coulomb. What is the magnitude of the electrostatic force acting on the electron?

(1) $3.75 \times 10^{21}$ N
(2) $6.00 \times 10^{2}$ N
(3) $9.60 \times 10^{-17}$ N
(4) $2.67 \times 10^{-22}$ N

42. The current in a wire is $4.0$ amperes. The time required for $2.5 \times 10^{19}$ electrons to pass a certain point in the wire is

(1) $1.0$ s
(2) $0.25$ s
(3) $0.50$ s
(4) $4.0$ s

43. When two point charges of magnitude $q_{1}$ and $q_{2}$ are separated by a distance, $r$ , the magnitude of the electrostatic force between them is $F$ . What would be the magnitude of the electrostatic force between point charges $2q_{1}$ and $4q_{2}$ when separated by a distance of $2r$ ?

(1) $F$
(2) $2F$
(3) $16F$
(4) $4F$

44. The composition of a meson with a charge of $-1$ elementary charge could be

(1) $s \overline{c}$
(2) $d s s$
(3) $u\overline{b}$
(4) $\overline{ucd}$

45. Which graph represents the relationship between the kinetic energy and the speed of a freely falling object?

(1)
(2)
(3)
(4)

46. Which diagram represents the electric field between two oppositely charged conducting spheres?

(1)
(2)
(3)
(4)

47. Which graph represents the relationship between the magnitude of the gravitational force, $F_{g}$ , between two masses and the distance, $r$ , between the centers of the masses?

(1)
(2)
(3)
(4)

48. The diagram below shows two waves traveling toward each other at equal speed in a uniform medium.

When both waves are in the region between points $A$ and $B$ , they will undergo

(1) diffraction
(2) the Doppler effect
(3) destructive interference
(4) constructive interference

49. The diagram below shows a series of straight wavefronts produced in a shallow tank of water approaching a small opening in a barrier.

Which diagram represents the appearance of the wavefronts after passing through the opening in the barrier?

(1)
(2)
(3)
(4)

50. The graph below represents the relationship between energy and the equivalent mass from which it can be converted.

The slope of this graph represents

(1) $c$
(2) $c^{2}$
(3) $g$
(4) $g^{2}$