Two resistors of values 6.0 and 12.0 W are connected in parallel. This combination in turn is hooked in series with a 4.0-W resistor and a 24-V battery. What is the current in the battery?
a. 12 A
c. 2.0 A
b. 3.0 A
d. 6.0 A
[Ques. 2] A toy gyroscope (a.k.
a. a top) consists of a solid disk with a thin rod projecting perpendicular to the center of the disk. The rod, which serves as the rotational axis for the gyroscope, projects on both sides of the disk. The gyroscope is placed with one end of the axis on the surface of the table, and spun so that the rotation of the disk viewed from above is counterclockwise. Alas, the axis of rotation is not quite perpendicular table surface and so the gyroscope precesses. Viewing from above, with the end of the axis in contact with the table staying in the same spot, in what direction does the other end of the axis of the gyroscope precess?
a. The precession is clockwise.
b. The precession is counterclockwise.
c. In the northern hemisphere the precession is clockwise, but in the southern hemisphere it is counterclockwise.
d. In the northern hemisphere the precession is counterclockwise, but in the southern hemisphere it is clockwise.
[Ques. 3] Two resistors of values 6.0 and 12.0 W are connected in parallel. This combination in turn is hooked in series with an 8.0-W resistor and a 24-V battery. What is the current in the 12-W resistor?
a. 1.3 A
c. 12 A
b. 4.0 A
d. 0.67 A
[Ques. 4] A Frisbee is thrown horizontally by a student and travels in a straight line. Viewed from above, the Frisbee is seen to be in clockwise rotation. From the point of view of the student, in which direction is the angular momentum of the Frisbee while in flight?
a. The Frisbee has no angular momentum since it is moving along a straight line away from the student.
b. The direction of the angular momentum is along the line away from the student.
c. The direction of the angular momentum is toward the right since this was a right-handed throw.
d. The direction of the angular momentum is downward, perpendicular to the path of the Frisbee.
[Ques. 5] Three resistors with values R1, R2, and R3, respectively, are connected in parallel. Which of the following expresses the total resistance, RT, of the three resistors when connected in parallel?
a. RT = (1/R1 + 1/R2 + 1/R3)
c. RT = R1 + R2 + R3
b. RT = R1 = R2 = R3
d. RT = (1/R1 + 1/R2 + 1/R3)-1
[Ques. 6] An astronomical unit (AU) is the average distance from the Earth to the Sun. An comet in orbit around the Sun has a perihelion (near point to the Sun) of 0.50 AU and an aphelion (far point from the Sun) of 5.0 AU. If the comet's orbital speed at aphelion is v, what is its speed at perihelion?
a. 11v
c. 5.5v
b. 10v
d. 4.5v
[Ques. 7] Three resistors connected in parallel have the individual voltages labeled DV1, DV2, and DV3, respectively. Which of the following expresses the total voltage DVT across the three resistors when connected in this manner?
a. DVT = (1/DV1 + 1/DV2 + 1/DV3)
c. DVT = (1/DV1 + 1/DV2 + 1/DV3)-1
b. DVT = DV1 + DV2 + DV3
d. DVT = DV1 = DV2 = DV3
[Ques. 8] Perihelion, the near point to the Sun for the Earth in its orbit, occurs in January. In which of the following months is the orbital angular momentum of the Earth the greatest?
a. only in January
b. only in July
c. in both April and October, but in no other months
d. None of the above answers is correct.
[Ques. 9] Three resistors connected in parallel each carry currents labeled I1, I2, and I3 . Which of the following expresses the value of the total current IT in the combined system?
a. IT = (1/I1 + 1/I2 + 1/I3)
c. IT = I1 + I2 + I3
b. IT = I1 = I2 = I3
d. IT = (1/I1 + 1/I2 + 1/I3)-1
[Ques. 10] A 6.0 kg mass in the xy plane is moving in the negative x direction at 3.0 m/s along the line y = 4.0 m. As the mass passes the point (x, y = 10 m, 4.0 m), what is its angular momentum with respect to the z axis?
a. 30 SI units
c. -60 SI units
b. 72 SI units
d. -180 SI units
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