Physical Setting 29 January 2009

Physical Setting 29 January 2009 Questions Answer Keys

The University of the State of New York
Regents High School Examination
Physical Setting
Physics
Thursday, January 29, 2009 — 1:15 to 4:15 p.m., only

Directions (1–30): For each statement or question, write on the separate answer sheet the number of the
word or expression that, of those given, best completes the statement or answers the question.

1. A force of 25 newtons east and a force of 25 newtons west act concurrently on a 5.0-kilogram cart. What is the acceleration of the cart?

(1) 1.0 m/s² west
(2) 0.20 m/s² east
(3) 5.0 m/s² east
(4) 0 m/s²

2. An unstretched spring has a length of 10. centimeters. When the spring is stretched by a force of 16 newtons, its length is increased to 18 centimeters. What is the spring constant of this spring?

(1) 0.89 N/cm
(2) 2.0 N/cm
(3) 1.6 N/cm
(4) 1.8 N/cm

3. What is the acceleration due to gravity at a location where a 15.0-kilogram mass weighs 45.0 newtons?

(1) 675 m/s²
(2) 9.81 m/s²
(3) 3.00 m/s²
(4) 0.333 m/s²

4. As a car is driven south in a straight line with decreasing speed, the acceleration of the car must be

(1) directed northward
(2) directed southward
(3) zero
(4) constant, but not zero

5. A baseball dropped from the roof of a tall building takes 3.1 seconds to hit the ground. How tall is the building? [Neglect friction.]

(1) 15 m
(2) 30. m
(3) 47 m
(4) 94 m

6. Which object has the greatest inertia?

(1) a falling leaf
(2) a softball in flight
(3) a seated high school student
(4) a rising helium-filled toy balloon

7. Centripetal force F_c acts on a car going around a curve. If the speed of the car were twice as great, the magnitude of the centripetal force necessary to keep the car moving in the same path would be

Note that question 8 has only three choices.

8. The diagram below represents the path of a stunt car that is driven off a cliff, neglecting friction.

Compared to the horizontal component of the car’s velocity at point A, the horizontal component of the car’s velocity at point B is

(1) smaller
(2) greater
(3) the same

9. What is the average power required to raise a 1.81 × 10⁴-newton elevator 12.0 meters in 22.5 seconds?

(1) 8.04 × 10² W
(2) 9.65 × 10³ W
(3) 2.17 × 10⁵ W
(4) 4.89 × 10⁶ W

10. If the speed of a moving object is doubled, the kinetic energy of the object is

(1) halved
(2) doubled
(3) unchanged
(4) quadrupled

11. Which statement best explains why a “wet saw” used to cut through fine optical crystals is constantly lubricated with oil?

(1) Lubrication decreases friction and minimizes the increase of internal energy.
(2) Lubrication decreases friction and maximizes the increase of internal energy.
(3) Lubrication increases friction and minimizes the increase of internal energy.
(4) Lubrication increases friction and maximizes the increase of internal energy.

12. The diagram below shows a toy cart possessing 16 joules of kinetic energy traveling on a frictionless, horizontal surface toward a horizontal spring.

If the cart comes to rest after compressing the spring a distance of 1.0 meter, what is the spring constant of the spring?

(1) 32 N/m
(2) 16 N/m
(3) 8.0 N/m
(4) 4.0 N/m

13. How much work is required to lift a 10.-newton weight from 4.0 meters to 40. meters above the surface of Earth?

(1) 2.5 J
(2) 3.6 J
(3) 3.6 × 10² J
(4) 4.0 × 10² J

14. Which situation describes a system with decreasing gravitational potential energy?

(1) a girl stretching a horizontal spring
(2) a bicyclist riding up a steep hill
(3) a rocket rising vertically from Earth
(4) a boy jumping down from a tree limb

15. If 20 joules of work is used to transfer 20 coulombs of charge through a 20-ohm resistor, the potential difference across the resistor is

(1) 1 V
(2) 20 V
(3) 0.05 V
(4) 400 V

16. At 20°C, four conducting wires made of different materials have the same length and the same diameter. Which wire has the least resistance?

(1) aluminum
(2) gold
(3) nichrome
(4) tungsten

17. Three identical lamps are connected in parallel with each other. If the resistance of each lamp is X ohms, what is the equivalent resistance of this parallel combination?

18. A 2.0-ohm resistor and a 4.0-ohm resistor are connected in series with a 12-volt battery. If the current through the 2.0-ohm resistor is 2.0 amperes, the current through the 4.0-ohm resistor is

(1) 1.0 A
(2) 2.0 A
(3) 3.0 A
(4) 4.0 A

19. The diagram below shows a beam of electrons fired through the region between two oppositely charged parallel plates in a cathode ray tube.

After passing between the charged plates, the electrons will most likely travel path

(1) A
(2) B
(3) C
(4) D

20. In which circuit would current flow through resistor R₁, but not through resistor R₂ while switch S is open?

21. The diagram below represents a 0.5-kilogram bar magnet and a 0.7-kilogram bar magnet with a distance of 0.2 meter between their centers.

Which statement best describes the forces between the bar magnets?

(1) Gravitational force and magnetic force are both repulsive.
(2) Gravitational force is repulsive and magnetic force is attractive.
(3) Gravitational force is attractive and magnetic force is repulsive.
(4) Gravitational force and magnetic force are both attractive.

22. A dampened fingertip rubbed around the rim of a crystal stemware glass causes the glass to vibrate and produce a musical note. This effect is due to

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

23. Which type of wave requires a material medium through which to travel?

(1) radio wave
(2) microwave
(3) light wave
(4) mechanical wave

Note that question 24 has only three choices.

24. Compared to the speed of a sound wave in air, the speed of a radio wave in air is

(1) less
(2) greater
(3) the same

Note that question 25 has only three choices.

25. If the amplitude of a wave is increased, the frequency of the wave will

(1) decrease
(2) increase
(3) remain the same

26. Which unit is equivalent to meters per second?

(1) Hz•s
(2) Hz•m
(3) s/Hz
(4) m/Hz

27. Which characteristic is the same for every color of light in a vacuum?

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

28. What is the speed of light (f = 5.09 × 10¹⁴ Hz) in flint glass?

(1) 1.81 × 10⁸ m/s
(2) 1.97 × 10⁸ m/s
(3) 3.00 × 10⁸ m/s
(4) 4.98 × 10⁸ m/s

29. While playing, two children create a standing wave in a rope, as shown in the diagram below. A third child participates by jumping the rope.

What is the wavelength of this standing wave?

(1) 2.15 m
(2) 4.30 m
(3) 6.45 m
(4) 8.60 m

30. A television remote control is used to direct pulses of electromagnetic radiation to a receiver on a television. This communication from the remote control to the television illustrates that electromagnetic radiation