PHYSICS 8A Lecture Notes - Lecture 5: Contact Force, Net Force
CHAPTER 4:NEWTON 's LAWS 6/25
.Force : a vector
,
causes /changes motion
.types of forces:
1) gravitational (E) :long -
range ,
always ads downward
2) normal (A): contact fore
,
Lto surface
3) tension (F) :contact Forum upsetting
4) friction (F) :contact force that acts Xto surfaces
,opposes relative motion
i)static : no nd . motion
btv surfaces
it Kinetic :there is
" "
.Net force :Ee+=FaFI
,
sum of all tones on an obj
.Newton
's 1st Law :an obj @rest
remains @net +an obj in motion aunt .
@const vunless a
anet force acts on it →const 8when Fneti ON
.Newton's 24 Law :for aparticular obj ,
EaFmt
,
Kldmatss
.
I4Fasts
INewton (IN)is the force needed to a cut
.a1kg obj @Imk '[KITT
tenet '
-mat
inertial ref
.
frame : in which N's laws hold -ie .
.
Earth's surface
.Free Body Diagram (FBD :
-can tilt axis so there are fewer component vectors to calculate
x*:x
⇐k¥
±i**
.
Weight (ht :Fu,
=Iin Kuralt
=Ma =gm
J= may
