PHYSICS 151

University of Hawaii, Manoa
Dept. of Physics & Astronomy

Instructor: Michael Nassir
Office: Watanabe Hall, Rm. 426, (808) 956-2922
E-mail: nassir @ hawaii.edu

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ANSWERS to MIDTERM #3 from SPRING 2003 

Part A

1. F
2a. C
2b. D
3. A and E
4. D
5. A
6a. E
6b. B
6c. D
6d. A
7. C
8. B
9. E

Part B

1a. v_final = 1.47 m/s (using conservation of momentum)
1b. E
1c. h = 0.110 m or 11.0 cm (using conservation of energy or using kinematics)

2a. total KE = 126.9 J or 127 J (translational KE = 90.6 J, rotational KE = 36.3 J)
2b. h = 1.78 m (using conservation of energy)
2c. C (The greater the rolling object's moment of inertia, the greater its rotational KE, and hence the greater its total KE, so the greater its final height. The hollow cylinder is like a hoop, so it has the greatest moment of inertia; the sphere has less moment of inertia; the ice cube has zero moment of inertia -- it doesn't spin at all.)

3. F_tension = m * g / (2 * sin a)