Physics Engineering 1 (Phys. 213) Practice Exam 4, Apr. 4th, 2008 (O'Shea)
Name __________________________________ Instructions: Please Read! This is a closed book, closed notes exam. This exam contains multiple-choice questions and problems. For each multiple-choice question, circle the letter of the best response. For problems, you need to show your work in a professional manner and write the final numerical answer with the proper unit in the space shown. Numerical answers without supporting calculations will receive zero credit. Partial credit is available only if your work is clear. 1. Academic honesty statement. This exam will NOT be marked unless you sign the academic honesty statement below. Your signature indicates that you have read, understood, and complied with the meaning of this statement. On my honor as a student I have neither given nor received unauthorized aid on this assignment.
Sign your name:__________________________________________________________
2. (1 point) Circle your Studio instructor/hour:
Lynch /TU 9:30
Matloob /TU 11:30
Regehr /TU 1:30
O'Shea/WF 7:30
Lynch /WF 9:30
Page total: /1
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3. The speed v versus time t for a 0.500 kg object of radius 6.00 cm that rolls smoothly down a 30 ramp is shown. a) What is the linear acceleration?
b) What distance the does the object roll during the time interval 0 1 seconds?
c) What is the rotational inertia of the object?
4. A solid ball radius r = 1 cm is rolling at an initial speed of vi as shown If it just makes it around the loop, radius R = 1.4 m, what is the value of vi? The ball rolls without slipping.
R
vi
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5. An overhead view of a thin uniform rod of length 0.600 m and mass M rotating horizontally at 80.0 rad/s counterclockwise about an axis through its center is shown. A particle of mass M/3.00 and traveling at speed 40.0 m/s hits the rod and sticks to it. The particle's path is perpendicular to the rod at the instant of the hit, at a distance d from the rod's center. a) At what value of d are rod and particle stationary after the hit?
b) In which direction do rod and particle rotate if d is greater than this value?
6. A meter stick balances horizontally on a knife-edge at the 50.0 cm mark. With two 5.00 g coins stacked over the 12.0 cm mark, the stick is found to balance at the 45.5 cm mark. What is the mass of the meter stick?
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7. A 50.0 kg uniform square sign, of edge length L = 2.00 m, is hung from a horizontal rod of length dh = 3.00 m and negligible mass. A cable is attached to the end of the rod and to a point on the wall at distance dv = 4.00 m above the point where the rod is hinged to the wall. [Hint: consider the mass of the sign to be located at the position of its center of mass] (a) What is the tension in the cable?
b) What are the magnitude and direction (left or right) of the horizontal component of the force on the rod from the wall,
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8. With what speed will an object hit Moon the if it is dropped from 100 km above the Moon's surface? The acceleration due to gravity at the moon's surface is 1.67 m/s2 and RMoon = 1.74 x 106 m.
9. The mean distance of Neptune, an outer planet of our solar system, from the Sun is 30 times that of Earth from the Sun. Calculate the number of years required for Neptune to make one revolution around the Sun
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Multiple choice (each question is worth 3 points unless otherwise noted) 10. When the speed of a rear-drive car is increasing on a horizontal road the direction of the frictional force on the tires is: a) forward for all tires b) forward for the front tires and backward for the rear tires c) backward for all tires d) backward for the front tires and forward for the rear tires e) zero 11. A solid wheel with mass M, radius R, and rotational inertia MR2 /2, rolls without sliding on a horizontal surface. A horizontal force F is applied to the axle and the center of mass has an acceleration a. The magnitudes of the applied force F and the frictional force f of the surface, respectively, are: a) F = Ma, f = 0 b) F = Ma, f = Ma/2 c) F = 2Ma, f = Ma d) F = 2Ma, f = Ma/2 e) F = 3Ma/2, f = Ma/2 d) None are correct 12. A thin-walled hollow tube rolls without sliding along the floor. The ratio of its translational kinetic energy to its rotational kinetic energy (about an axis through its center of mass) is: a) 1 b) 2 c) 3 d) e) 1/3 13. A hoop, a uniform disk, and a uniform sphere, all with the same mass and outer radius, start with the same speed and roll without sliding up identical inclines. Rank the objects according to how high they go, least to greatest. a) hoop, disk, sphere b) disk, hoop, sphere c) sphere, hoop, disk d) sphere, disk, hoop e) hoop, sphere, disk 14. A man, with his arms at his sides, is spinning on a light frictionless turntable. When he extends his arms: a) his angular velocity increases b) his angular velocity remains the same c) his rotational inertia decreases d) his rotational kinetic energy increases e) his angular momentum remains the same 15. A uniform 0.25 kg meter stick can be balanced by a 0.25 kg weight placed at the 100 cm mark if the fulcrum is placed at the point marked: a) 75 cm b) 60 cm c) 50 cm d) 40 cm e) 80 cm 16. A planet has a mass of about 0.0558 times the mass of Earth and a diameter of about 0.381 times the diameter of Earth. The acceleration of a body falling near the surface of this planet is about: a) 0.21m/s2 b) 1.4m/s2 c) 2.8m/s2 d) 3.8m/s2 e) 25m/s2 17. Neglecting air resistance, a 1.0-kg projectile has an escape velocity of about 11 km/s at the surface of Earth. The corresponding escape velocity for a 2.0 kg projectile is: a) 3.5 km/s b) 5.5 km/ c) 7.1 km/s d) 11 km/s e) 22 km/s 18. A particle has coordinates x = 2 m, y = 3 m, z = 0. A forces is applied to the particle v along the +y axis. The direction of , the torque about the origin is: a) +x b) x c)+y d) y e)+z f)-z
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