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Force and Motion. What is a Force?. FORCE = Any push or pull which causes something to move or change its speed or direction. What is a Force?. Forces can be BALANCED or UNBALANCED Balanced forces are equal in size and opposite in direction
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What is a Force? FORCE = Any push or pull which causes something to move or change its speed or direction
What is a Force? Forces can be BALANCED or UNBALANCED • Balanced forces are equal in size and opposite in direction • Unbalanced forces are not equal in size and/or opposite in direction. If the forces on an object are UNBALANCED, we say a NET force results.
What is a Force? Can you think of examples of forces? • Balanced Forces? • Unbalanced Forces?
What is Gravity? GRAVITY: An attraction force between all masses • Newton’s universal law of gravitation: Every object in the universe exerts a gravitational attraction to all other objects in the universe • The amount of gravitational force depends upon the mass of the objects and the distance between the objects
What is Gravity? • The greater the mass, the greater the force • The greater the distance, the less the force
Weight is a measure of the gravitational force between two objects • The greater the mass the greater the force (weight) • Measured in units called Newtons (N)
Air resistance: The force of air exerted on a falling object • The air pushes up as gravity pulls down • Dependent upon the shape and surface area of the object • Terminal velocity is the highest velocity that an object will reach as it falls
What is Motion? Motion: A change in position of an object compared to a reference point Motion involves all of the following:
What is Motion? = distance time
What is Friction? Friction = A force that opposes or slows down motion • Caused by the physical contact between moving surfaces • The amount of friction depends upon the kinds of surfaces and the force pressing the surfaces together • Changes motion into heat
What is Friction? What are some ways athletes uses friction?