The
work
W
done by a constant
force
acting on an object is
where
F
is
the magnitude of the force,
s
is the magnitude of the displacement, and
θ
is the angle
between the force and the
displacement
vectors.
Work
is a
scalar
quantity and can be
positive or negative, depending on whether the force has a
component
that points,
respectively, in the same direction as the displacement or in the opposite direction. The
work is zero if the force is perpendicular
= 90 ° to the displacement.
The
kinetic energy
KE of an object of
mass
m
and speed
v
is
The
work–
energy theorem
states that the
work
W
done by the net external
force
acting on an object
equals the difference between the object's final
kinetic energy
KE
f
and initial kinetic
energy KE
0
:
W
= KE
f
 KE
0
. If the net force does positive work, the kinetic energy
increases; if the net force does negative work, the kinetic energy decreases.
The
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This note was uploaded on 04/09/2008 for the course PHYS 101 taught by Professor Sharp during the Spring '08 term at Ohio State.
 Spring '08
 Sharp
 Force, Work

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