PHYS 1110_ch2_v3.pptx - PHYS 1110 Engineering Physics Mechanics and Thermodynamics Ch2 Force and Motion 2.1 2.2 2.3 2.4 2.5 Newtonian Mechanics

# PHYS 1110_ch2_v3.pptx - PHYS 1110 Engineering Physics...

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PHYS 1110 Engineering Physics: Mechanics and Thermodynamics
Ch2. Force and Motion 2.1 Newtonian Mechanics 2.2 Newton’s First Law of Motion 2.3 Newton’s Second Law of Motion 2.4 Newton’s Third Law of Motion 2.5 Some Particular Forces
2.1 Newtonian Mechanics Three laws of motion (empirical) – basis for classical mechanics Describe the relation b etween a force and the motion it causes Can be applied to the motion of objects rang ing in size from the ve ry small to astronomic al. Isaac Newton (1642 – 1727)
2.2 Newton’s First Law of Motion
2.2 Newton’s First Law of Motion Newton's first law of motion : all objects resist c hange in their state of motion. All objects have t his tendency; i.e. they have inertia The mass of an object is a measure of its inertia Larger mass more inertia larger tendency t o resist changes in its state of motion The mass of an object is usually given in units of g (gram) or kg (kilogram)
Frame of Reference?Tom threw the ball vertically upwards on a train moving with constant velocity .2.2 Newton’s First Law of Motion
2.2 Newton’s First Law of Motion
Examples of noninertial frames : Rotating frame A ball is released from the person sitting on the flying chair. There is no horizontal force on the ball. From the reference frame of a person sitting on the flying chair, the ball seems to move on a curve path. Th e motion of the ball seems not to obey Newton’s laws of motion in th is reference frame In short, all inertial frames are non-accelerating . Picture from - choice/ Flying chair ride Ball release d at this point Chair undergoi ng uniform circular motion s Chair undergoi ng uniform circular motion A short time later 2.2 Newton’s First Law of Motion
2.3 Newton’s Second Law of Motion
2.3 Newton’s Second Law of Motion Definition of Force In modern notation, we often find Newton’s Seco nd Law as: For deeper understanding, we rewrite the R.H.S. a s: If the mass of the object is constant
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