About the Exam

1
About the Exam

• EXAM will begin promptly at 900 am
• Closed book, closed notes
• Test will consist of 3 problems and 5 multiple
  choice questions.
• Bring a pencil and calculator
• Paper will be provided

2
Outline

• Chapter 7 - Rotational Motion
• Rotational Kinematic Eqns.
• Centripetal Acceleration
• Newtonian Gravitation
• Chapter 8 - Rotational Dynamics
• Torque
• Mechanical Equilibrium
• Newtons 2nd Law (Rotational)
• Rotational K.E.
• Energy Conservation

• Chapter 5 - Energy
• Work
• Work-Energy Theorem
• Potential Kinetic Energy
• Energy Conservation
• Power
• Chapter 6 - Momentum
• Impulse
• Impulse-Momentum Theorem
• Conservation of Momentum
• 1D 2D Collisions

3
Study Strategies

• Start now!
• Do lots (and lots) of practice problems
• Study with a class mate
• Get enough sleep

4
Test taking strategies

• Look through the entire test to see what problems
  you immediately know how to do and do them first!
• Check your numerical answers to see that they do
  make sense
• Make sure your answers include correct units
• If you do not know how to do a problem, write
  down what you do know

5
Q1

• A fly ball to left field is caught at the same
  height as it was originally hit. Over its entire
  flight the work done by gravity and the work done
  by air resistance, respectively, are
• 0 positive
• 0 negative
• positive negative
• negative positive
• negative negative

6
Q2

• Two marbles, one twice as heavy as the other, are
  dropped to the ground from the roof of a
  building. Just before hitting the ground, the
  heavier marble has
• As much kinetic energy as the lighter one.
• Twice as much kinetic energy as the lighter one.
• Half as much kinetic energy as the lighter one.
• Four times as much kinetic energy as the lighter
  one.
• Impossible to determine

7
Q3

• A person holds a 20 N weight two meters above the
  floor for 30 seconds. The power required to do
  this is
• 4/3 W
• 40 W
• 40 h.p.
• 120 J-s
• None of these

8
Q4

• Suppose a ping-pong ball and a bowling ball are
  rolling toward you. Both have the same momentum,
  and you exert the same force to stop each. How
  do the time intervals to stop them compare?
• It takes less time to stop the ping-pong ball.
• Both take the same time.
• It takes more time to stop the ping-pong ball.

9
Q5

• Suppose rain falls vertically into an open cart
  rolling along a straight horizontal track with
  negligible friction. As a result of the
  accumulating water, the speed of the cart
• increases.
• does not change
• decreases.

10
Q6

• A 75-kg man is riding in a 30-kg cart at 2.0 m/s.
  He jumps off in such a way as to land on the
  ground with no horizontal velocity. The
  resulting change in speed of the cart is
• Zero
• 2.0 m/s
• 3.0 m/s
• 4.0 m/s
• 5.0 m/s

11
Q7

• The approximate value of g (in m/s2) at an
  altitude above Earths surface equal to one Earth
  diameter is
• 9.8
• 4.9
• 2.5
• 1.9
• 1.1

12
Q8

• The moon does not crash into the Earth because
• The net force on it is zero
• It is beyond the pull of Earths gravity
• It is being pulled away by the sun and the other
  planets.
• Its acceleration toward the Earth is zero
• None of the above

13
Q9

• A small object of mass m, on the end of a light
  cord, is held horizontally at a distance r from a
  fixed support as shown. The object is then
  released. What is the tension in the cord when
  the object is at the lowest point of its swing?
• mg/2
• mg
• 2mg
• 3mg
• mgr

r
m
14
Q10

• A ladybug sits at the outer edge of a turn table,
  and a gentlemanbug sits halfway between her and
  the axis of rotation. The turntable makes a
  complete revolution once each second. The
  gentlemanbugs tangential speed is
• half the ladybugs
• the same as the ladybugs
• twice the ladybugs
• impossible to determine

15
Q11

• A force with a given magnitude is to be applied
  to a wheel. The torque can be maximized by
• applying the force near the axle, radially
  outward from the axle
• applying the force near the rim, radially outward
  from the axle
• applying the force near the axle, parallel to a
  tangent to the wheel
• applying the force at the rim, tangent to the rim
• applying the force at the rim, at 45? to the
  tangent

16
Q12

• The rotational inertia of a body tends to cause
  the body to
• produce more torque
• rotate slower over time
• maintain its rotational motion
• change its angular momentum
• change its rotational kinetic energy

17
Q13

• Three identical point masses of mass M are
  fastened to a massless rod of length L as shown.
  The rotational inertia about one end of the rod
  of this array is
• ML2/2
• ML2
• 3ML2/2
• 5ML2/4
• 3ML2

m
m
m
L/2
L/2
18
Q14

• A hoop (I mR2), a uniform disk (I 0.5 mR2),
  and a uniform sphere (I 0.4mR2), all with the
  same mass and outer radius, start with the same
  sped and roll without slipping up identical
  inclines. Rank the objects according to how high
  they go, least to greatest.
• hoop, disk, sphere
• disk, hoop, sphere
• sphere, hoop, disk
• sphere, disk, hoop
• all three tie