1. Review of Quiz 4 Total: 50 Average: 28.4 High: 47 Low: 5 11/24/2018
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2. Problem 1
Problem 1 (5 points): Suppose a 7.5kg mass is rotating about an axis at a distance of 5 m. What is the object’s moment of inertia about the axis?
a) 38 kg-m2 b)190 kg-m2 c)280 kg-m2 d)400 kg-m2
Answer:
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3. Problem 2
Problem 2 (5 points): What is the vector product of AxB if A=3i and B=4j?
a) 3i + 4j b) 0 c) 0.7i d) 12k
Answer:
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4. Problem 3
Problem 3 (5 points): A post is driven perpendicularly into the ground and serves as the axis about which a gate rotates. A force of 12N is applied perpendicular to the gate and acts parallel to the ground. How far from the post should the force be applied to produce a torque of 3.0 Nm?
a) 0.25m b) 4.0m c) 36m d) 12 m
Answer:
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5. Problem 4
Problem 4 (5 points): A constant torque of 30Nm is applied to a merry-go-round for 10 seconds. Neglecting friction what is the magnitude of the change of the merry-go-round’s angular momentum?
a)3kg-m2/s b)0.3kg-m2/s c) 300kg-m2/s d) 3kg-m2/s
Answer:
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6. Problem 5
Problem 5 (5 points): A disk of 4.0 kg and 0.20 m is rotating about its axis of symmetry at w =10 rads/sec. What is the rotational kinetic energy?
Answer
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7. Problem 6
Problem 6 (10 points): Starting from rest a 5.0kg cylinder of radius 0.5m rolls down an inclined plane without slipping or sliding. How much will the height of the cylinder have decreased when the velocity is 10m/s?
+5pts
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8. +5pts
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9. Problem 7
Problem 7(15points): As shown in the figure, a diver of weight 530 N is poised at the right end of a diving board. The board has length 3.90 m. The board has negligible weight and is bolted down at the left end while supported 1.4 m away by a fulcrum. Draw the equilibrium diagram with all three forces involved. Find the forces F1 and F2 that the bolt and fulcrum exert on the board.
+5pts
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10. +5pts
+5pts
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11. A Narrative: Where We’ve Been
Started by describing linear motion with constant acceleration, free fall, and projectile motion.
Studied Newton’s 2nd Laws and Law of Gravitation and saw how these can be quantitatively applied to many systems.
Laws naturally lead to concepts of work, energy, and conservation of energy and momentum.
Finally applied these to find complete analog to rotational motion.
We can now describe the mechanical universe over an immense range of distances: a top, a hurricane, and a galaxy. A true achievement and always fun!
Next semester you’ll carry these tools into electromagnetism, in particular vector operations, energy conservation, and potential fields.
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12. Final Comprehensive Multiple Choice Problems
Eight questions
Five points each
Problems
Six Questions
Points:
Two Five point questions
Two Ten point questions
Two Fifteen point questions
Partial Credit Given!
Open Book You may bring my notes as well, (but that seems like needlessly killing trees.)
Calculators will be needed
All Material Covered:
Chapters 1-11
Chapter 12, Sections 1,2,3,4
Chapter 14, Sections 1,2
100 Points
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13. Computing Grades Four quizzes - 50 points each – 200 points maximum.
Final exam points points maximum.
Unit problem sets - 12 points each, due before quiz – 84 points maximum.
Fourteen laboratories - 15 points each points maximum. (Note: Each student must get 120 points or more in the laboratory to pass the course, regardless of other scores.)
Extra credit – Each problem worth one point. Final extra credit is equal to the fraction of problems correct times points maximum.
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14. Grade Scale A : 535 or more points B : 475 to 534 points
C : 416 to 474 points
D : 357 to 415 points
F : less than 357 points
(If necessary may be adjusted for curve)
If you want your grade stop by or send me !
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15. Final Exam Topics & Problems
Unit conversion
Motion in two dimensions and projectile motion
Free-body analysis with normal, frictional, and gravitational forces involved.
Definition of non-conservative and conservative forces and examples.
Definition and application of work for linear motion
Conservation of mechanical energy
Elastic force and energy
Gravitational force and conservation of energy
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16. Scattering in one dimension Vector Operations (addition, dot, vector)
Moment of Inertia
A free-body analysis involving forces, torque, and moments of inertia
Qualitative understanding of tops and precession
Calculating the impact of the Coriolis force
A statics problem involving forces and torques
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