Transcript Notes: Forces Big “G” and little “g”

Notes: Forces
Big “G” and little “g”
Newton’s Law of Universal Gravity
Fg, the force of attraction between
two objects is directly proportional to
the products of the masses of the
objects, and inversely proportional to
square of the distances between
their centers of mass
Fg = G m1m2
r2
G = 6.67 x 10-11 Nm2
kg2
m1
m2
F1
F2
r
m1
m2
F1
F2
r
Fg = G m1m2
r2
Force of gravity (Fg) between
large masses (objects) is
greater than between small
masses (objects).
Force of gravity (Fg) decreases
as distance between objects
increases.
Acceleration due to the force
of gravity
All falling objects on earth, in the
absence of air resistance,
accelerate at the rate of 9.8 m/s2
g = 2Dd = 9.8 m/s2
t2
Vf = gDt
Vf = √2gDd
Dd = 1gt2
2
air resistance (or drag) the force
exerted by air on a moving object
terminal velocity
the largest velocity that is reached by
a falling object
when air resistance balances the pull
of gravity, an object stops
accelerating and its speed remains
constant
Big “G”, Little “g”, and “Fg”
“G” is a constant value used to
calculate the force of gravity
between two objects.
G = 6.67 x 10-11 Nm2
kg2
“g” is the acceleration due to the
force of gravity pulling on an object
“Fg” is the actual pull, or force, of
gravity on an object. It is also the
weight of an object.
“Pulling ‘g’s’ ” in an aircraft, or
amusement park ride, is actually
the measure of how many times
your weight “Fg “ your body is
experiencing.