5 Newton

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5 Newtons Laws of Motion5-1 Force and Mass

• Question How is acceleration induced? ?v/?t

Baseball
Force influence that causes a body to
acceleration Mass how difficult to change its
velocity quantity of matter in object
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5-2 Newtons first law of Motion

• An object at rest remains at rest as long as
  no net force acts on it.
• An object moving with constant velocity
  continues to move with the same speed and in the
  same direction as long as no net force acts on it.

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• Law of inertia
• if an object is already moving with constant
  velocity, it wont alter its speed or direction ,
  unless a force causes the change.

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5-3 Newtons Second Law of Motion

• Mass constant

Force constant
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sum of force vectors
Vector acceleration and force , Direction
acceleration is same as net force. Force Unit 1
N(1kg)(1 m/s2)
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• Ex1.
• Mass of a car 2000kg, the accelerate is 4
  m/s2, find force?
• Ex2.
• A box from 0 to 0.7 m/s in 3s, m20kg, find
  net force?

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• Net force

Ex3.
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Newtons second law
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Free-Body diagram

• Isolate the object of interest (point particle)
• Sketch the forces (every external force acting on
  a given object)
• Choose a convenient coordinate system
• Resolve the force into components
• Apply Newtons second law to each coordinate
  direction