PHYS171_f11_lecture_42

PHYS171_f11_lecture_42 - different To be in static...

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

View Full Document Right Arrow Icon
PHYS171 Chapter 11 Problem A cylindrical turntable of radius R , mass M rotates on a rigid, frictionless axle at angular frequency ω 0 . A piece of clay of mass m drops onto the turntable and sticks a distance r from the center. Find the final frequency of rotation. Determine change in kinetic energy. Determine if linear momentum is conserved. ( M =30kg, m=2.25kg, R =1.9m, r =1.8m, ω 0 =4 π )
Background image of page 1

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

View Full DocumentRight Arrow Icon
Chapter 12 Static Equilibrium and Elasticity Previously: For an object to be in equilibrium we must require that the sum of all forces is zero. Now: We are taking into account that objects are generally not point-like If an object is not rotating, then we must also require that the sum of all torques is zero. Chapter 12 Static Equilibrium and Elasticity O r F θ F r F r r r × = τ , = = 0 0 v v F
Background image of page 2
Chapter 12 Static Equilibrium and Elasticity O r F θ F r F r r r × = τ , = = 0 0 v v F If I choose a different axis the torque arising from the force F will be
Background image of page 3

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

View Full DocumentRight Arrow Icon
Background image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: different To be in static equilibrium, the net force must be zero and the net torque most be zero when evaluated about any axis. Chapter 12 Static Equilibrium and Elasticity O r F F r F r r r = , r F If the net force is zero and the net torque is zero about any axis, it is zero about all possible axes. Chapter 12 Static Equilibrium and Elasticity mg F r F r r r = , The center of gravity of an object is the same as the center of mass (in a uniform gravitation field). Therefore gravity doesnt tend to rotate an object about its center of mass. It can rotate an object about an arbitrarily defined axis of rotation. mg mg mg Chapter 12 Problem You stand on a horizontal beam supported by a wire. Find the tension. m M, L x M = 20kg m = 60kg L = 8 m x = 2m = 53...
View Full Document

Page1 / 4

PHYS171_f11_lecture_42 - different To be in static...

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

View Full Document Right Arrow Icon
Ask a homework question - tutors are online