7. If 10 kg of ice at 0 oC is mixed with 100 kg of water at 80 oC and is additionally heated with 4620 kJ, what is the final temperature of the water? (The heat capacity constant of water is 4.2 kJ∙kg^-1 ∙K ^-1 , and the latent heat of fusion of water is 333 kJ∙kg^-1 .)
(A) 45 oC
(B) 55 oC
(C) 65 oC
(D) 70 oC
(E) 75 oC

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)

4. A disk with a radius of 2.0 m and a rotational inertia of 0.40 kg·m 2 rotates with an angular speed of 4.0 rad/s around a frictionless vertical axle. A wade of clay (m = 25 g) drops onto and sticks to the edge of the disk. What is the new angular speed of the disk? (A) 3.2 rad/s (B) 3.6 rad/s (C) 2.7 rad/s (D) 1.1 rad/s (E) 0.67 rad/s

5. A violin is played with an initial intensity  Ii  changing to a final intensity If. If If = 5 Ii , what 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)

6. An engine is designed to obtain energy from the temperature gradient of the ocean. What is the thermodynamic efficiency of such an engine if the temperature of the surface of the water is 15 °C and the temperature below the surface is 5 °C?(A) 96% (B) 67% (C) 31% (D) 17% (E) 3.5%

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

 9. A proton moves around a circular path (radius = 2.0 mm) in a uniform 0.25 T magnetic field. What total distance does this proton travel during a 1.0 s time interval? (mp = 1.67×10-27 kg, q = 1.6× 10-19 C) (A) 82 km (B) 59 km (C) 71 km (D) 48 km (E) 7.5 km

10. A current loop freely rotates in a uniform magnetic field (B = 0.50 T). The maximum torque on the loop is 0.60 N ∙ m. What is the magnetic dipole moment of the loop? (A) 1.2 A·m 2 (B) 2.4 A·m 2 (C) 0.60 A·m 2 (D) 0.30 A·m 2 (E) 0.83 A·m 2

11. A 2.0 kΩ resistor and an initially uncharged 6.0 μF capacitor are connected in series to a 12 V battery. A switch is closed to complete the circuit at t = 0. What is the voltage across the resistor at t = 1.0 s?(A) 0 V (B) 12 V (C) 6 V (D) 3 V (E) 9 V

 12. A 3 μF capacitor is connected in series with a 6 μF capacitor. When a 300 V potential difference is applied across this combination, the total energy stored in the two capacitors is ______. (A) 0.09 J (B) 0.18 J (C) 0.27 J (D) 0.41 J (E) 0.81 J

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.