Lecture 8 - Visualizing Forces Flashcards

- do practice math questions!

1
Q

what is a force?

A
  • an action that causes mass to be accelerated
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2
Q

what are Isaac Newton’s 3 Laws?

A
  1. objects don’t want to be accelerated because they possess inertia
  2. the force required to accelerate an object is proportional to it’s mass (F = m x a)
  3. if a force is applied to an object, the object pushes back with the same force
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3
Q

what is the law of inertia?

A
  • mass doesn’t want to be accelerated
  • if staying still wants to remain still
  • if moving, wants to remain moving at that speed
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4
Q

what is the law of force?

A
  • m is a scalar
  • acceleration and force go in the same direction
  • amount of force needed can be determined by acceleration x mass
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5
Q

what is the law of action/reaction?

A
  • amount of force put into an object is returned (proportional)
  • heavy objects return more force (painful)
  • light object return less force (which is why they move)
  • the ball doesn’t care what the foot is doing and vice versa (force acts on different objects which causes movement)
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6
Q

what is the property of mass?

A
  • magnitude (measured in kg)
  • only 1 because scalar
  • amount of matter that makes up an object
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7
Q

what is the difference between mass and weight?

A
  • mass is scalar, weight is a force (because of gravity)
  • astronauts have the same mass in space but their weight is different
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8
Q

what are the properties of weight?

A
  • a force (gravity)
  • measured in newtons (N) or lbs
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9
Q

what are the 4 properties of a force?

A
  • force is a vector
    1. has a magnitude
    2. has a direction
    3. has a point of application (where force is being applied)
    4. has a line of action (where force has been and where it is going)
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10
Q

what is the center of mass?

A
  • point of application of gravity
  • aka center of gravity
  • doesn’t have to be within the object
  • can move around as body moves and weight is redistributed
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11
Q

when might it be useful to put the center of mass outside of the body?

A
  • lower center of mass = less force required
  • for example: with high jump (fosbury flop)
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12
Q

what are the components of force?

A
  • resultant force = the line of force an object has (made up of horizontal and downward forces)
  • angle of push = angle between horizontal and downward force you are pushing at (Pythagorean theorem)
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13
Q

what are non-orthogonal forces?

A
  • means the input forces are not at 90 degrees from each other
  • us F1 and F2 (instead of horizontal and downwards)
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14
Q

what is collinear force?

A
  • all lines of action are parallel
  • moving straight up while holding a weight for example
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15
Q

what are the steps to draw a resultant force graphically?

A
  1. draw the line of push (from POA)
  2. draw a horizontal direction (from POA)
  3. draw a vertical direction (from POA)
  4. complete the rectangle
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