Classical Mechanics Friction: Examples Work

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Classical Mechanics Friction ExamplesWork
Kinetic Energy
Midterm 2 will be held on November 8. Covers
units 4-9
JFB Rotunda David Matthew Stephens Lei Shan
(Mike)
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Schedule
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Schedule
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Schedule
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Coupled Blocks with Friction
A block (m2) slides on a table pulled by a string
attached to a mass (m1) hanging over the side.
The coefficient of kinetic friction between the
sliding block and the table is mk. What is the
tension in the string?
m2
g
m1
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Tension in String

A block (m2) slides on a table pulled by a string
attached to a mass (m1) hanging over the side.
The coefficient of kinetic friction between the
sliding block and the table is mk. What is the
tension in the string?
T1
T2
m2
g
What is the relationship between the magnitude of
the tension of the string at block 2 and the
magnitude of the tension in the string at block
1? A) T1 gt T2 B) T1 T2 C) T1 lt T2
m1
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Acceleration of coupled blocks

A block (m2) slides on a table pulled by a string
attached to a mass (m1) hanging over the side.
The coefficient of kinetic friction between the
sliding block and the table is mk. What is the
tension in the string?
m2
g
m1
What is the relationship between the magnitudes
of the acceleration of the two blocks? A) a1 a2
B) a1 lt a2 C) a1 gt a2
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m2
1) FBD
N
T
m2
g
f
T
m1
m1
m2g
m1g
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m2
1) FBD 2) SFma
N
T
m2
g
f
T
m1
m1
m2g
N m2g
m1g
m1g T m1a
T m m2g m2a
add
m1g m m2g m1a m2a
m1g m m2g
a
m1 m2
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m2
1) FBD 2) SFma
N
T
m2
g
f
T
m1
m1
m2g
m1g
m1g T m1a
m1g m m2g
T m1g m1a
a
m1 m2
T is smaller when a is bigger
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Accelerating Blocks
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Accelerating Blocks
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Carnival Ride
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Carnival Ride
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Accelerating Truck
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Accelerating Truck
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Mass on Incline
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Mass on Incline
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Mass on Incline
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Mass on Incline 2
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Mass on Incline 2
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Mass on Incline 2
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Mass on Incline 2
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Block
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Pushing Blocks
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Classical Mechanics Lecture 7
Midterm 2 will be held on November 8. Covers
units 4-9

• Todays Concepts
• Work Kinetic Energy

JFB Rotunda David Matthew Stephens Lei Shan
(Mike)
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Lecture Thoughts
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Kinetic Energy and Work
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Work-Kinetic Energy Theorem

• The work done by force F as it acts on an object
  that moves between positions r1 and r2 is equal
  to the change in the objects kinetic energy

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What about Potential Energy??.next Unit!
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Work-Kinetic Energy Theorem

• The work done by force F as it acts on an object
  that moves between positions r1 and r2 is equal
  to the change in the objects kinetic energy

But again!!!
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Newtons 2nd law? Work Kinetic Energy
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Vector Multiplication
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The Dot Product
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The Dot Product
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The Dot Product
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Work Kinetic Energy Theorem Work on sliding box
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Work Kinetic Energy Theorem
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Work done by Weight
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Work Kinetic Energy Theorem Applied
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Work done by a Spring
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Main Points
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Main Points
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Main Points