所屬科目:學士後西醫-物理
2.A ball is thrown horizontally from the top of a 20-m high hill. It strikes the ground at an angle of ㆍ450. With what speed was it thrown? Use g = 10 m/s2. (A) 14m/s (B) 20m/s (C) 28 m/s (D) 32 m/s(E) 40 m/s
4.Block A, with a mass of 10 kg, rests on a 30* incline. The coefficient of kinetic friction is 0.20. The attached string is parallel to the incline and passes over a massless, frictionless pulley at the top. Block B, with a mass of 8.0 kg, is attached to the dangling end of the string (take √3 1.7 and g =10 m/s2). The acceleration of B is:
(A) 0.72 m/s2, up (B) 0.72 m/s2, down (C) 2.6 m/s2, , up (D) 2.6 m/s2, down (E) 0 m/s2
6.As a 2.0-kg object moves from m, the constant resultant force acting on it is equal to N. If the speed of the object at the initial position is 4.0 m/s, what is its kinetio energy at its final position? (A)62 J (B)53J (C)73J (D)86J (E)24 J
11. The figure shows a uniform rod (length L = 1.0 m, mass m = 2.0 kg) suspended from a pivot a distance d = 0.25 m above its center of mass. If the angular frequency for small oscillations is ω, then ω2 , in (rad/s)2, is approximately (Given the moment of inertia about a perpendicular axis through the center of mass is = mL2 /12 and take g = 10 m/s2) (A)1.0 (B)6.25 (C) 2.25 (D) 17.1 (E) 12.25
12. A ball of mass me is released from rest and acquires velocity of magnitude vB before hitting the ground. The ratio of the kinetic energy the Earth (mass ) acquires to the kinetic cnergy the ball acquires is m: (A) 0. (B) (C) (D) 1. (E)
19. While temperature is kept constant, if consider only translational and rotational motion, what is the total energy of 1 liter of nitrogen gas with pressure of I atm (take 1 atm=105 Pa)? (A)0.1kJ (B)0.15kJ(C)0.2kJ(D)0.25 kJ(E) 0.35 kJ
22. Water is streaming downward from a faucet opening with an area of . It lcaves the faucet with a specd of 5.0 m/s. The cross-sectional area of the stream 0.55 m below the faucet is how many : (Take g = 10 m/s2. ) (A)1.5(B)2.0 (C)2.5 (D)3.0(E) 3.5
25. Determine the minimum area of a flat ice floe 1.0 meter thick if it is to support a 2 000-kg car above seawater. ( = 920 kg/m3, = 1 020 kg/m3.) (A)20m2(B)40m2 (C)60m2(D)80m2 (E) 100m2
26. At what rate is thermal energy being generated in the 2R-resistor when ε = 12 V and R = 3.0 Ω? (A)12 W (B) 24 W (C) 6.0 W (D)3.0 W (E)1.5 W
28. As shown in the figure, a wire and a 10-Ω resistor are used to form a circuit in the shape of a square, 20 cm by 20 cm. A uniform but nonsteady magnetic field is directed into the plane of the circuit. The magnitude of the magnetic field is decreased from 1.50 T to 0.50 T in a time interval of 63 ms. The average induced current and its direction through the resistor, in this time interval, are closest to
32. Determine the energy stored in C2 when C1 = 15 MF, C2 = 10 MF, C3 = 20 uF, and V0 = 18 V. Xx (A)0.72 mJ (B)0.32 mJ (C)0.50 mJ (D)0.18 m.J (E)1.60 mJ
34. A 16-nC charge is distributed uniformly along the x axis from x = 0 to x = 4 m. Which of the following integrals is correct for the magnitude (in N/C) of the electric field at x = +10 m on the x axis? (A)(B)(C)(D)
37. When a cube is inscribed in a sphere of radius r, the length L of a side of the cube is L = . If a positive point charge Q is placed at the center of the spherical surface, the ratio of the electric flux Qsphere at the spherical surface to the flux Qcbe at the surface of the cube is(A)(B)(C) 1(D)(E)
38. For the potential Y = 3x2z - 2yz3, what is the corresponding electric field at the point (2,2,2)?(A)(B) (C) (D)
39. A square loop (L = 0.20 m) consists of 50 closely wrapped turns, each carrying a current of 0.50 A. The loop is oriented as shown in a uniform magnetic field of 0.40 T directed in the positive y
direction. What is the magnitude of the torque on the loop?(A) 0.21 Nㆍm(B) 0.20 N ㆍm (C) 0.35Nㆍm(D) 0.12 N ㆍm(E) 1.73 N ㆍm
40. A bar magnet is dropped from above and falls through the loop of wire shown below. The north pole of the bar magnet points downward towards the page as it falls. Which statement is correct?
(A) The current in the loop always flows in a clockwise direction. (B) The current in the loop always flows in a counterclockwise direction. (C) The current in the loop flows first in a clockwise, then in a counterclockwise. direction. (D) The current in the loop flows first in a counterclock wise, then in a clockwise. direction. (E) No current flows in the loop because both ends of the magnet move through the. loop
41. What is the magnitude of the magnetic ficld at point P if a = R and b = 2R? (A)(B)(C)(D)(E)
44. A loop of wire (resistance = 2.0 mΩ) is positioned as shown with respect to a long wire which carries a current. If d = 1.0 cm, D = 6.0 cm, and L = 1.5 m, what current(I) is induced in the loop at an instant when the current in the wire is increasing at a rate of 100 A/s? (A)34 mA(B)30 mA(C)27 mA(D)38 mA(E)0.50 mA
45. A conducting rectangular loop of mass M, resistance R, and dimensions a x b is allowed to fall from rest through a uniform magnetic field which is perpendicular to the plane of the loop. The loop accelerates until it reaches a terminal speed (before the upper end enters the magnetic field). If a = 2.0 m, B = 6.0 T, R= 40 2, and M = 0.60 kg, what is the terminal speed? (A) 1.6 m/s (B) 20 m/s (C) 2.2 m/s (D) 26 m/s (E) 5.3 m/s
46. A conducting sphere of radius R carries an excess positive charge and is very far from any other charges. Which one of the following graphs best illustrates the potential (relative to infinity) produced by this sphere as a function of the distance r from the center of the sphere? (A)(B)(C)(D)(E)
48. Point charges q and Q are positioned as shown. If q = +2.0 nC, Q = -2.0 nC, a = 3.0 m, and b = 4.0 m, what is the clectric potential difference, ? (A)8.4 V (B)6.0 V (C)7.2 V (D)4.8 V (E) O V