Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.
Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.
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Can anyone help me to answer these two questions please?
1) How much will the angular acceleration of a disk decrease if we were to decrease the force by a factor of 13.6?
2) How will the angular acceleration of a disk increase if we were to increase the radius by a factor of 3.02?
I have tried to figure out how to set up the ratios so as to solve these but I'm still having trouble understanding how they should be set up. If I can at least get the first step I should be able to figure out.
Last edited by bud2 (2009-03-29 00:18:31)
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those problems are just appaulingly expressed.....
what is "the force" ? the force on the disc i am to presume.. but where and how is this force pressing or is it a torque??
MMmmm the angular acceleration... mmm what is that,,, i presume the angular velocity w is changing so i guess it is dw/dt. OK. But the answer will depend on the mass, or rather angular inertia... whats the name... ((angular momentum is angular velocity times "moment of inertia")) ... thats the name
We need the moment of inertia ... is it given ???? then torque equals angular accln times moment of inertia (like a rotational version of f=ma)
2nd problem is really awful--- and non physical--- how exactly is the radius increased?? is it stretching on its own or being pulled or does someone stick some extra material on the outside to increase the radius ?? material (mass) cannot just suddenly change its location like in star trek, its contrary to Einsteins relativity and violates causality.
Where did you get these problems from ... maybe you forgot many important details ??
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