Newton

1
Newtons Second Law and Force Body Diagrams

• By
• Devin Sosnowski, Ryan Kotwica,
• Craig Reichel, and Jeff Zoellick

2
Terms

• net force the vector sum of all the forces
  acting on the body
• weight caused by mass accelerating downwards
  due to gravity
• force body diagram a diagram showing the
  directions or forces acting on an object.

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Concepts

• Newtons Second Law of Motion states the
  acceleration of a body is directly proportional
  to the force on it and inversely proportional to
  its mass

• This law may be summarized by the equation
• aF/m
• or more commonly known as
• Fma

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Force Body Diagrams
Fn
Fn
Ff
Fp
W
W
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More diagrams
Fn
Ff
A
Ft
W
A
W
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Examples from the Real World

• When you step on the accelerator in a car, you go
  forward.
• When the brakes are applied on a roller coaster,
  the train of cars slows down and comes to a stop.
• A bowling ball will accelerate (roll) faster with
  more force, but a bowling ball will roll slower
  than a basketball with the same amount of force
  because its less massive.

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Sample Problems

• Draw the force diagrams for an object
  deccelerating due to friction
• Draw an object in free fall
• Draw an object thats sliding on an angle with
  friction

• A 5kg bowling ball is accelerating down the lane
  at 2m/s/s. What is the Net Force?
• A 2000 kg pickup truck moves at constant speed of
  50 m/s down the street. What is its Net Force?

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Quiz Type Questions

• Accellerations are produced by
• A) Masses
• B) Accelerations
• C) Velocities
• D) Forces
• E) Something else!

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Quiz Type Questions

• Accellerations are produced by
• A) Masses
• B) Accelerations
• C) Velocities
• D) Forces
• E) Something else!

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Quiz Type Questions

• An object following a straight line path at
  constant speed _______.
• A) must be moving in a vacuum.
• B) has no forces acting on it.
• C) has a net force acting on it in the direction
  of motion.
• D) has zero acceleration.
• E) none of the above.

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Quiz Type Questions

• An object following a straight line path at
  constant speed _______.
• A) must be moving in a vacuum.
• B) has no forces acting on it.
• C) has a net force acting on it in the direction
  of motion.
• D) has zero acceleration.
• E) none of the above.

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