所屬科目:物理
1. Two boxes are connected by a string, as shown below. The string and pulley are massless, and m1+m2=16 kg. If the system is at rest and the coefficient of static friction is 0.6, what is the minimum weight of m1? (A) 4 kg (B) 6 kg (C) 8 kg (D) 10 kg (E) 12 kg
3. A thin uniform rod of mass M and length L is positioned vertically above an anchored frictionless pivot point, as shown below, and then allowed to fall to the ground. At what speed does the free end of the rod strike the ground? (A) (B)(C)(D)(E)
5. A violin is played with an initial intensitywhat is the difference in sound intensity level (dB) between these two extremes? (A) 10(log5) (B) 5 (C) 10 (D) 10(log2) (E) 2(log5)
8. Some species of whales can dive to the depth of one kilometer. What is the approximate total pressure they experience at this depth? (ρsea = 1020 kg/m3 and 1 atm =1.01 ×105 N/m2 ) (A) 9.00 atm (B) 90.0 atm (C) 100 atm (D) 111 atm (E) 130 atm
13. A magnetic field is directed out of the page. Two charged particles enter from the top and take the paths shown in the figure. Which statement is correct? (A) Particle 1 has a positive charge and particle 2 has a negative charge. (B) Particle 1 has a negative charge and particle 2 has a positive charge. (C) Both particles are negatively charged. (D) Both particles are positively charged. (E) The direction of the paths depends on the magnitude of the velocity, not the sign of the charge
31. As the figure shows, a stone was thrown on the roof of height h=10 m from the throw. After 6 seconds, the stone fell on the roof at a horizontal distance d from the throw. The angle between the final flight path of the stone and the roof is Θ = ° 60 . Then, the horizontal distance d it travels is: (A) 166.5 m (B) 333.0 m (C) 144.2 m (D) 288.4 m (E) 55.5 m
32. A force
33. A 10 g bullet moving 1000 m/s strikes and passes through a 2.0 kg block initially at rest, as shown. The bullet emerges from the block with a speed of 400 m/s. What is the maximum height at which the block will rise above its initial position? (A) 78 cm (B) 66 cm (C) 56 cm (D) 46 cm (E) 37 cm
34. A box of mass 1 kg was placed on the edge of a rotating table with radius 10 cm, as shown below. At what rotating speed, the box begins to slide away? (The coefficient of static friction between the box and table is 0.8) (A) 32 cm/s (B) 53 cm/s (C) 68 cm/s (D) 89 cm/s (E) 98 cm/s
36. A uniform beam of weight 300 N and length 3.0 m is suspended horizontally. On the left it is hinged to a wall; on the right it is supported by a cable bolted to the wall at distance D above the beam. The tension on the cable is 250 N. What value of D corresponds to that tension? (A) 1.25 m (B) 1.50 m (C) 1.75 m (D) 2.00 m (E) 2.25 m
37. A forceis applied on a particle. What is the work done by the force as the particle moves in an x-y plane from (1.0 m, 0.0 m) to (-2.0 m, 3.0 m)? (A) 15 J (B) 1.0 J (C) 3.0 J (D) 17 J (E) 11 J
38. A single conservative forceacts on a particle that moves along an x axis. The particle has mass of 2.0 kg. The potential energy associated withis described by =, where x is in meters. What is the value of x whereis equal to zero? (A) -1.0 m (B) 1.0 m (C) 0.5 m (D) -0.5 m (E) 0 m
39. In the figure, a block of mass m = 20.0 kg slides through a horizontal frictionless ground at a speed of v = 0.50 m/s. It then compresses the spring with spring constant k = 5.0 N/m. When the block decelerates to a stop, by what distance d is the spring compressed? (A) 0.5 m (B) 1.0 m (C) 1.5 m (D) 2.0 m (E) 2.5 m
41. A pipe open at both ends has a fundamental frequency of f..A second pipe closed at one end and open at the other end has the same fundamental frequency. What is the ratio of the length of the pipe open at both ends to the length of the pipe closed at oneend?(A)1(B)2(C)(D)4(E)
43. An object is located at 40 cm from the first of two thin converging lenses of focal lengths 20 cm and 10 cm, respectively, as shown in the figure above. The lenses are separated by 30 cm. The final image formed by the two-lens system is located ______. (A) 5.0 cm to the right of the second lens (B) 13.3 cm to the right of the second lens (C) infinitely far to the right of the second lens (D) 13.3 cm to the left of the second lens (E) 100 cm to the left of the second lens
44. Two stars are separated by an angle of 3 × 10−5 radians. What is the diameter of the smallest telescope that can resolve the two stars using visible light (λ600 nm)? (Ignore any effects due to Earth’s atmosphere.) (A) 1 mm (B) 2.5 cm (C) 10 cm (D) 2.5 m (E) 10 m
45. Unpolarized light of intensity I0is incident on a series of three polarizing filters. The axis of the second filter is oriented at 45° to that of the first filter, while the axis of the third filter is oriented at 90o to that of the first filter. What is the intensity of the light transmitted through the third filter?(A)0(B)(C)(D)(E)
46. If a gas undergoes a series of pressure (P) and volume (V) changes, as shown below, how much work is done by the gas along the path a→b→c→d→e→f→a? (A) 20 J (B) 30 J (C) 40 J (D) 50 J (E) 60 J
47. There is a laminar flow in a tube. When both the radius and length of the tube are doubled, how many times of flow resistance is changed?(A)(B)(C)(D)(E)
48. A steam of water of density ρ, cross-sectional area A, and speed υ strikes a wall that is perpendicular to the direction of the stream, as shown in the figure below. The water then flows sideways across the wall. The force exerted by the stream on the wall is ______.(A)(B)(C)(D)(E)
51. A 5.0 A current flows along a wire withm. The wire resides in a uniform magnetic field T. The magnetic force acting on the wire is described by
52. The current in an inductor (L = 40 mH) is described by with I in ampers and t in seconds. What is the magnitude of the emf induced in the inductor at t = 3.0 s? (A) 2.0 V (B) 0.080 V (C) 50 V (D) 0 V (E) 4.0 V
53. A stiff wire bent into a semicircle of radius a = 2.0 cm is rotated at constant angular speed 40 rev/s in a uniform 20 mT magnetic field. What is the amplitude of the emf induced in the loop? (A) 3.16 × 10-2 V (B) 3.16 × 10-3 V (C) 3.16 × 10-1 V (D) 1.98 × 10-2 V (E) 1.98 × 10-3 V
54. Three long wires parallel to the x axis carry currents as shown. If I = 20 A, what is the magnitude of the magnetic field at the origin point O? ( magnetic constant μ0 = 4π × 10-7 T·m/A ) (A) 19 μT (B) 28 μT (C) 37 μT (D) 47 μT (E) 58 μT
55. The coil shown below has 2 turns, a cross-sectional area of 0.20 m2 , and a field (parallel to the axis of the coil) with a magnitude given by B = (4.0 + 3.0t 2 ) T, where t is in s. What is the potential difference, VA - VC, at t = 3.0 s? (A) -7.2 V (B) +7.2 V (C) -4.8 V (D) +4.8V (E) -12 V
56. A series RLC circuit is connected to an ac source (). The resistance, capacitive reactance and inductive reactance are 40 Ω, 80 Ω, and 50 Ω respectively. What is the current (I
57. The rest mass of an electron is mo. What is the kinetic energy of an electron with the speed of 0.80c? (The constant c is the speed of light in vacuum.)(A)(B)(C)(D)(E)
58. In the hydrogen spectrum, the ratio of the wavelengths for Lyman-α radiation (n = 2 to n = 1) to Balmer-α radiation (n = 3 to n = 2) is ______.(A)(B)(C)(D)3(E)