Conservation of Mechanical Energy

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Conservation of Mechanical Energy

• Cody Mainwaring
• Physics 2005-2006
• Wauzeka Steuben School District

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THE PROBLEM

• A Large chunk of ice with a mass of 15.9 kg falls
  from a roof 8.0 m above the ground.
• Ignoring the air resistance, find the kinetic
  energy of the ice when it reaches the ground.
• What is the speed of the ice when it reaches the
  ground.

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THE EQUATION
PROBLEM "A"
U
mgh
g1
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PROBLEM "A"

• Ignoring air resistance, find the kinetic energy
  of the ice when it reaches the ground.
• Known Unknown
• m15.0kg Ug1?
• h8.0m K2?
• g9.80m/s v2?
• K10
• Ug20

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CALCULATIONS PROBLEM "A"
Ug1mgh (15.0kg)(9.80m/s2)(8.0m) 1.8x103j K
2Ug11.18x 103j
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PROBLEM "B"

• WHAT IS THE SPEED OF THE ICE
• CHUNK WHEN IT REACHES THE
• GROUND???

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CALCULATION "B"
K2 1/2 mv2 2 V2 v2K2 / m v 2(1.18x103J) /
15.0 kg 12.5 m/s