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- Dec 1, 2011
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I'm stuck on the whole concept of mechanical advantage. There is a problem in the momentum chapter that states "What is the mechanical advantage associated with a lever system made of a 2 meter long stick with the fulcrum at the .5 meter mark. In the chapter the equation for MA is weight of object/applied force needed to support object.
Secondly, for angular momentum, is KE always conserved if no external forces present, etc? There is a problem that asks what will happen to angular velocity and KE if moment of inertia is increased by factor of 3. I said KE wouldn't change b/c it would be conserved but that is wrong. The answer is that KE decreases by factor of 3 and W decreases by a factor of 3 as well. Can someone explain why KE changes and is not conserved? Thanks!!!
Secondly, for angular momentum, is KE always conserved if no external forces present, etc? There is a problem that asks what will happen to angular velocity and KE if moment of inertia is increased by factor of 3. I said KE wouldn't change b/c it would be conserved but that is wrong. The answer is that KE decreases by factor of 3 and W decreases by a factor of 3 as well. Can someone explain why KE changes and is not conserved? Thanks!!!