1. MHS Physics Department AP Unit I E 2 Torque and rotational statics

2. MHS Physics Department A) Students should understand the concept of torque, so they can: (1) Calculate the magnitude and direction of the torque associated with a given force. (2) Calculate the torque on a rigid body due to gravity. (b) Students should be able to analyze problems in statics, so they can: (1) State the conditions for translational and rotational equilibrium of a rigid object. (2) Apply these conditions in analyzing the equilibrium of a rigid object under the combined influence of a number of coplanar forces applied at different locations.

3. MHS Physics Department Torque Torque (τ) = Force (F) x perpendicular distance (r) from the pivot or point of rotation τ = rF Sin θ Torque is measured in N m

4. MHS Physics Department Conditions for Equilibrium Translational Equilibrium ΣF = 0 Rotational Equilibrium Στ = 0

5. MHS Physics Department Center of gravity Lies on axis of symmetry

6. MHS Physics Department Moment of Inertia Moment of Inertia I = Σ m r 2 α = angular acceleration (ω 2 – ω 1 )/ Δt Στ =I α

7. MHS Physics Department Rotational Kinetic Energy K R = ½ I ω 2

8. MHS Physics Department Angular momentum Angular Momentum L must always be conserved L = I ω Example: Skater spinning on ice Satellites in orbit