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Physics 2053. Lecture Notes. Rotational Equilibrium and Rotational Dynamics. Rotational Motion 1 of 25. Rotational Equilibrium and Dynamics. Topics. 9-01 Torque. 8-02 Torque and the Conditions for Equilibrium. 8-03 Center of Gravity. 8-04 Examples of Objects in Equilibrium.
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Physics 2053 Lecture Notes Rotational Equilibrium and Rotational Dynamics Rotational Motion 1 of 25
Rotational Equilibrium and Dynamics Topics 9-01 Torque 8-02 Torque and the Conditions for Equilibrium 8-03 Center of Gravity 8-04 Examples of Objects in Equilibrium Dynamics: Newton’s Laws of Motion
Torque r F Torque The force used to open a door produces a torque Static Equilibrium
Rotational Equilibrium Two equal forces are applied to a door. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Both forces are applied perpendicular to the door. Which force exerts the greater torque? A) the first at the midpoint B) both exert equal non-zero torques C) both exert zero torques D) the second at the doorknob Rotational Equilibrium
Torque r q F R Torque Static Equilibrium
Rotational Equilibrium Two equal forces are applied to a door at the doorknob. The first force is applied perpendicular to the door; the second force is applied at 30° to the plane of the door. Which force exerts the greater torque? A) the first applied perpendicular to the door B) the second applied at an angle C) both exert equal non-zero torques D) both exert zero torques Rotational Equilibrium
Torque and the Conditions for Equilibrium Conditions for Equilibrium SF = 0 St = 0 Static Equilibrium
Torque and the Conditions for Equilibrium N = ? 2nd Condition of Equilibrium 1st Condition of Equilibrium What is the Distance x2 What is the Normal Force A massless meter stick x3 = 20 cm x2 = ? o 3 kg 2 kg Static Equilibrium
Center of Gravity xcm y m2 m1 x cg x1 x2 Linear Momentum
Problem y x Find the center of gravity of the three-mass system shown in the diagram. Specify relative to the left-hand 1.00 kg mass. 1.0 kg 1.5 kg 1.1 kg 0.5 m 0.25 m Linear Momentum
Center of Gravity L L = 150 cm W = 600 N Wb= 50 N F = 200 N Find xcg Linear Momentum
Center of Gravity L N F L = 150 cm W = 600 N Wb= 50 N F = 200 N Linear Momentum
Examples of Objects in Equilibrium N1 N2 WB WT Truck on a Bridge 1st Condition 2st Condition Static Equilibrium
Examples of Objects in Equilibrium WT Truck on a Bridge N1 N2 WB 1st Condition 2nd Condition Static Equilibrium
Examples of Objects in Equilibrium T F N WB WS Physics Hanging a Sign q Static Equilibrium
Examples of Objects in Equilibrium Hanging a Sign d = L sin(q) Find Tension in cable d T F 1st Condition N q A L WB WS 2nd Condition Static Equilibrium
Examples of Objects in Equilibrium T F N WS WB d L How far (d) can a student walk on beam before cable breaks (Tmax) q Static Equilibrium
Examples of Objects in Equilibrium L d Tmax F q o N WS WB Walking Student When T reaches Tmax Static Equilibrium