Lecture 11: Laws of motion - Sonoma Valley High School

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Transcript Lecture 11: Laws of motion - Sonoma Valley High School

Lecture 11: Laws of motion
Newton’s 1st Law: Inertia
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Matter resists motion
If at rest, it will stay
at rest
If in motion, it will
stay in motion
Mass is a measure of
inertia
Newton’s 2nd Law
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An unbalanced force
acts on objects
equal to its mass
and acceleration
F=mXa
F = force
m = mass
a = acceleration
Gravity
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All objects in the
universe attract each
other
Gravity is a function
of mass and
distance
More mass= more
gravity
More distance = less
gravity
Weight and gravity
The pull of gravity on
Earth is 9.8m/s 2
Weight is mass X the pull of
gravity (w=mg)
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Q: are weight and mass the
same?
Q: do we weigh the same
on the moon as on earth?
Terminal velocity
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The maximum speed
objects fall to earth is
200 mi/h or 320km/h
How does the
parachute slow the
fall?
Newton’s 3rd Law
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Forces act in pairs
For every action
force, there is an
equal and opposite
reaction force
Momentum = mass X velocity
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The greater the mass,
the greater the
momentum.
Ex: semi trucks take
longer to stop than
cars.
Q: will momentum be
greater at more
velocity?
Action and reaction force pairs