AP Unit I C 2,3

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AP Unit I C 2,3

• Conservative forces

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• A) Students should understand the concept of a
  conservative force so they can-
• (4) Write an expression for the force exerted by
  an ideal spring and for the potential energy of a
  stretched or compressed spring.
• (5) Calculate the potential energy of one or more
  objects in a gravitational field.

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I C 3

• A) Students should understand the concepts of
  mechanical energy and of total energy so they can
• (2) Describe and identify situations in which
  mechanical energy is converted to other forms of
  energy.
• (3) Analyze situations in which an objects
  mechanical energy is changed by friction or by a
  specified externally applied force.

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• B) Students should understand conservation of
  energy, so they can
• (1) Identify situations in which mechanical
  energy is or is not conserved.
• (2)Apply conservation of energy in analyzing the
  motion of systems of connected objects, such as
  Atwoods machine.
• (3) Apply conservation of energy in analyzing the
  motion of objects that move under the influence
  of springs (horizontal and vertical)

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2.(4) Springs series and parallel

• Springs in series, extension is doubled Springs
  in parallel, extension is halved.

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2. (5) Potential Energy U

• Gravitational Potential Energy
• Ug mgh
• Spring Potential energy
• Us ½ F x ½ k x2

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3. A)(2) Roller Coaster

• Potential energy is converted into kinetic energy
  and vice versa.

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3. a) (3) Braking

• Car mass 3 500.0 kg brakes from 60.0 m/s to 30.0
  m/s over a distance of 2.00 km. Calculate force
  applied by brakes.

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3.b)(1) Swinging Pendulum

• Potential energy is converted into kinetic energy
  and vice versa.

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3.b)(2) Atwood machine

• http//hyperphysics.phy-astr.gsu.edu/hbase/atwd.ht
  ml

   a (M - m)/(M m)g
FT (M m)a FM - Fm (Mg-mg) g(M-m)
T
T
m
mg
M
Mg
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3. B) (3) Oscillating Horizontal and vertical
springs.

• Spring potential Energy is transferred in the
  form of kinetic energy
• ½ kx2 ½ mv2

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Forces on a slope
N mg cos ?
Fparallel mg sin ?
?
?
Fperpendicular mg cos ?
mg