Download Work - Solon City Schools

WORK
AP 1 chapter 6: section 6.1-6.2
WORK
The product of the magnitude of the displacement
times the component of the force PARALLEL to the
direction of motion.
Scalar but can be negative or positive (lose or
gain)
W=F”d =FdcosӨ
Ө is the angle between the force and the
direction of motion.
Units are Newton-meter (Nm)= Joule (J)
WORK CAN BE
Done by the object (-W)
Done on the object (+W)
Done by a specific force (must name it)
Done by a Net force
A PERSON PULLS A 50 KG CRATE 40 M ALONG A HORIZONTAL FLOOR BY A
CONSTANT FORCE OF 100N ACTING AT A 37°ANGLE. THE FLOOR IS ROUGH AND
EXERTS A FRICTIONAL FORCE OF 50N.
Wg done by gravity
=mgdcosӨ = 0
Find the work done by
each force.
WN done by FN
FN
Fa
=FNdcosӨ = 0
Wa done by person
=FadcosӨ= 100N(40m)cos 37 =3200J
Ff
Fg
Wf done by friction
=FfdcosӨ= 50N(40m)cos180 = -2000J
NET WORK ON CRATE
FN
Ff
Fg
Fa
Wnet= sum of all work
=0J + 0J +3200J + -2000J
=1200 J
OR
Wnet= Fnetd
=(Fa-Ff)d
=(100cos37-50)(40m)
FORCE VS DISPLACEMENT
Work is the area under the curve.
F” (N)
A=length*width=F”d=W
A=1/2(p+q)h
trapezoid
d (m)
A=1/2*base *height =1/2dF” =-W