# Week6a - Rotations and Matter Week Topics covered Section...

This preview shows pages 1–4. Sign up to view the full content.

Rotations and Matter Topics covered Week Topics: Rotations and Matter Section in Textbook 6 Static Equilibrium Rotation, Moment of Inertia Conservation of Angular Momentum Ch. 11 : 1-3 Ch. 9 : 1-5 Ch. 10 : 1-7 7 Gravity Fluids including surface tension Ch. 12 : 1-6 Ch. 14 : 1-6 8 Elasticity Thermal Expansion Oscillations Ch. 11 : 4-5 Ch. 17 : 4 Ch. 13 : 1-6 Learning Goals • Conditions for equilibrium • Centre of Gravity and its relation to stability • Problem solving for rigid bodies • Describe the rotation of a rigid body (angular coordinate, velocity and acceleration • analyze rigid body rotation under constant angular acceleration • Relate angular motion of a rigid body to linear velocity and acceleration at a point on the body • Moment of inertia about a rotation axis and its relation to rotational kinetic energy • How the net torque on a body affects the rotational motion of the body • Solving problems involving work and power for rotation bodies • Angular momentum of a rigid body and how it changes with time • Gyroscopic motion and precession Static Equilibrium Before rotation there was equilibrium! 1st condition for equilibrium of a particle or a body: therefore no tendency for linear acceleration (i.e. translation) 2 nd condition for equilibrium of a particle or a body: therefore no tendency for angular acceleration (i.e. rotation) Both conditions must be satisfied for static equilibrium = 0 F r = 0 τ r

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
The force of gravity is considered to act at the centre of gravity. (The same position as centre of mass) In a uniform symmetric body the centre of gravity is at the centre. In each of the following bodies the centre of gravity is marked c. Centre of Gravity For maximum stability the centre of mass of an object must be over the base of the object. Which object is harder to stop from falling over? Why? Isn’t the force of gravity the same in each case? Torque Torque or turning force is the lever arm times the applied force. The lever arm is the perpendicular distance between the line of action of the force and the axis of rotation. τ = F l = r x F (cross product) | τ | = r F sin θ The torque is negative if the torque is tending to rotate the object in the clockwise direction.
Cross Product The vector C is perpendicular to the plane containing the vectors A and B © Physics, Uni of Wollongong © Physics, Uni of Wollongong Rotation has direction Rotation in the clockwise direction has the vector into the page. A massless rod of length L is suspended

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 9

Week6a - Rotations and Matter Week Topics covered Section...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online