An 10.0-W resistor is dissipating 100 watts. What are the current through it and the difference of potential across it?
a. 31.6 A, 3.16 V
c. 3.16 A, 31.6 V
b. 10.0 A, 3.16 V
d. 3.16 A, 10.0 V
[Ques. 2] A turntable has a moment of inertia of 3.00 10-2 kgm2 and spins freely on a frictionless bearing at 25.0 rev/min. A 0.600-kg ball of putty is dropped vertically on the turntable and sticks at a point 0.100 m from the center. By what factor does the angular momentum of the system change after the putty is dropped onto the turntable?
a. 1.22
c. 0.820
b. 1.00 (no change)
d. 1.20
[Ques. 3] A solar panel measures 80 cm 50 cm. In direct sunlight, the panel delivers 4.8 A at 15 V. If the intensity of sunlight is 1000 W/m2, what is the efficiency of the solar panel in converting solar energy into electrical energy?
a. 12
c. 18
b. 24
d. 6.0
[Ques. 4] A turntable has a moment of inertia of 3.00 10-2 kgm2 and spins freely on a frictionless bearing at 25.0 rev/min. A 0.600-kg ball of putty is dropped vertically onto the turntable and sticks at a point 0.100 m from the center. What is the new rate of rotation of the system?
a. 20.8 rev/min
c. 33.3 rev/min
b. 22.7 rev/min
d. 27.2 rev/min
[Ques. 5] An electric car is designed to run off a bank of 12-V batteries with total energy storage of 6.0 107 J. If the electric motor draws 6000 W in moving the car at a steady speed of 10 m/s, how far will the car go before it is out of juice?
a. 150 km
c. 100 km
b. 50 km
d. 25 km
[Ques. 6] A figure skater on ice with arms extended, spins at a rate of 3.5 rev/s. After he draws his arms in, he spins at 6.0 rev/s. By what factor does the skater's kinetic energy change when he draws his arms in?
a. 2.4
c. 0.58
b. 1.7
d. 0.12
[Ques. 7] A high-voltage transmission line carries 500 A at 700 kV for a distance of 100 miles. If the resistance in the wire is 1 W/mile, what is the power loss due to resistive losses?
a. 250 MW
c. 25 MW
b. 2.5 kW
d. 25 kW
[Ques. 8] An ice skater spins at 3.5 rev/s with his arms are extended. He draws his arms in and spins at 8.3 rev/s. By what factor does his moment of inertia change in the process?
a. 2.4
c. 0.42
b. 0.58
d. 0.12
[Ques. 9] A high-voltage transmission line carries 500 A at 700,000 V. What is the power carried by the line?
a. 100 MW
c. 700 MW
b. 350 MW
d. 70 MW
[Ques. 10] A figure skater with arms initially extended starts spinning on the ice at 3 rad/s. She then pulls her arms in close to her body. Which of the following results?
a. a smaller rotational rate
c. a greater angular momentum
b. a greater rotational rate
d. a smaller angular momentum
Quick Reply
