1. mg x L

2. Center of Gravity Weighted Average
Gravitational force acts on all points of an extended object
However, it can be considered as one net force acting on one point, the center-of-gravity, X.
Weighted Average

3. Torque and Angular Acceleration
Analogous to relation between F and a
Moment of Inertia

4. Conserved if no net outside torques Conserved if no net outside forces
Angular Momentum
Rigid body
Point particle
Analogy between L and p
Angular Momentum
Linear momentum
L = Iw
p = mv
t = DL/Dt
F = Dp/Dt
Conserved if no net outside torques
Conserved if no net outside forces

5. ∆d = ∆θ.r v =ω.r a = α.r 2θ = (ωf + ωi)t θ = ωit + ½αt2 ωf = ωi + αt
Answers
∆d = ∆θ.r
v =ω.r
a = α.r
2θ = (ωf + ωi)t
θ = ωit + ½αt2
ωf = ωi + αt
ωf2 = ωi2 + 2αθ
 = F.l
 = Iα
L = Iω
KE = ½Iω2
1) 2508 N.m
2) 1.36 x 10-4 N.m
3) 40 N.m; 50 sec
4) 61,328 N.m
5) 4.85 N
6) 452 ft.lbs
7) 0.04 N
point mass : I=MR2