_____________ is a push or a pull Force is a push or a pull
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- _____________ is a push or a pull
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- Force is a push or a pull.
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- Effect of force depends on:
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- 1. Magnitude (strength) 2. Direction of the force
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- Force is measured in:
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- Pounds English System Newtons SI (System International)
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- Force can be measured by spring balances or ____________.
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- Force can be measured by spring balances or scales
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- ___________ forces equal and opposite. __________ forces one
side stronger. Gives a NET FORCE.
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- Balanced forces equal and opposite. Unbalanced forces one side
stronger. Gives a NET FORCE.
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- ___________ - shows only magnitude (strength) Examples:
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- Scalars - shows only magnitude (strength) Examples:
Temperature, Elapsed time, pressure and mass.
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- __________ - shows both magnitude and direction. Examples:
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- Vectors - shows both magnitude and direction. Examples: Force,
displacement, velocity, acceleration and momentum.
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- Vector lines are drawn with an arrow. ___________ = magnitude
of vector (strength) ___________ = direction the force is
acting.
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- Vector lines are drawn with an arrow. Length of arrow =
magnitude of vector (strength) Direction of arrow = direction the
force is acting.
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- 2 or more forces in the same direction you can add to get the
total force (net force). 2 or more forces in the opposite
direction, you subtract to get the net force.
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- If forces dont act along the same line you cannot add or
subtract. You have to graph and measure the resulting line (or use
trigonometry). You have 30 lbs pulling North and 40 lbs pulling
East. What is the resulting force?
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- 1. Chose a scale (say 1 cm 10 lbs) 2. Graph the 2 forces at the
correct angle matching the head of one line to the tail of the
other line. 3. Draw the resultant line. Measure that line and use
your scale to determine its magnitude.
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- _________ is force in rotation mechanical systems. It is
measured in ___________ or __________ T=F x L
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- Torque is force in rotation mechanical systems. Measured in lb
ft or N m T = F x L
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- Torque = _____________ x _____________ ____________ is the
shortest distance from the rotation axis to the line of
action.
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- Torque = applied force x lever arm The lever arm is the
shortest distance from the rotation axis to the line of
action.
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- If the lever arm is 12 inches (1 foot) and you use 40 lbs of
force to turn it find the torque:
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- T = F x L 40 lbs x 1 ft = 40 lb ft
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- You need 80 Nm of torque to turn a bolt. You can apply 100
Newtons of force. How long of a wrench (lever arm) do you
need?
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- T = F x L 80 = 100 x L 80/100 =.8m T =.8 m