Review of Quiz 4

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Review of Quiz 4

• Total 50
• Average 28.4
• High 47
• Low 5

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 objects moment of inertia about the axis?
• a) 38 kg-m2 b)190 kg-m2 c)280 kg-m2 d)400
  kg-m2
• Answer

3
Problem 2

• Problem 2 (5 points) What is the vector product
  of AxB if A3i and B4j?
• a) 3i 4j b) 0 c) 0.7i d) 12k
• Answer

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

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-rounds angular momentum?
• a)3kg-m2/s b)0.3kg-m2/s c) 300kg-m2/s d)
  3kg-m2/s
• Answer

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

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
8
5pts
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
10
5pts
5pts
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A Narrative Where Weve Been

• Started by describing linear motion with constant
  acceleration, free fall, and projectile motion.
• Studied Newtons 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 youll carry these tools into
  electromagnetism, in particular vector
  operations, energy conservation, and potential
  fields.

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Final

• Comprehensive
• Multiple Choice
• 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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Computing Grades

• Four quizzes - 50 points each 200 points
  maximum.
• Final exam - 100 points - 100 points maximum.
• Unit problem sets - 12 points each, due before
  quiz 84 points maximum.
• Fourteen laboratories - 15 points each - 210
  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 70 - 70 points maximum.

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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 email!

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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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• 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