Ex) Compound Wheel Find Net Torque, Both F =50. N r_{1} = 30 cm, r_{2} = 50 cm
A 30 cm disk and a 50. cm disk are attached to an axle that passes through their centers. If a 50. N force hangs from the 30. cm disk and a 50. N force is applied to the 50. cm disk a shown above what is the net torque on the compound wheel CW negative CCW positive
t_{net} = = .30 m(50. N)  .50 m(50. N)cos120°
 6.7 mN
Ex 2) A 2.20 m uniform beam with a mass of 25.0 kg has a 28.0 kg sign attached to it. Find all the forces on the beam
Find the tension on the cable T and the components of wall's force on the beam F_{wally} F_{wallx}
_{I. Finding Cable Tension} St = 0
TsinqL = mgL/2+MgL
Tsinq = mg/2+Mg
Tsin30 = mg/2+Mg
T/2 = mg/2+Mg
Ex 2) A 2.20 m uniform beam with a mass of 25.0 kg has a 28.0 kg sign attached to it.
T = mg + 2Mg = 25.0 kg(9.8 m/s^{2})+ 2(28.0 kg)(9.8 m/s^{2})
T = 794 N
II. Find F_{wally} & F_{wallx}
Tcosq = F_{wallx}
=794 Ncos30
F_{wallx }= 687 N
II. Find F_{wally}
SF_{y} = 0
mg + Mg = F_{wally }+ Tsin30
F_{wally} = 123 N
Giancoli  p. 248) 18, 20, 21
ŠTony Mangiacapre.,
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