http://ocw.mit.edu/courses/physics/8-01sc-physics-i-classical-mechanics-fall-2010/conservation-of-angular-momentum/MIT8_01SC_quiz25_sols.pdf
check out the problem 5...
Then what is the force pulling the ball inwards?...voodoo?...:|...there is an obvious decrease in the radius...this displacement according to ur theory is caused by no force?..initially there is no inward velocity...so all of a sudden it moves in?...sounds spooky...So much for Newton's 1st...
I am sorry but the kinetic energy does increase...but the mechanical energy of the net system is conserved..
yes..the calculation is simple...i have posted it above...if u do find any error in those calculations please do tell me..
The centripetal force in this case work in pulling the ball inwards...and if u want to know how the centripetal force came into existence it would be from the electrostatic attractions..
Agreed...that is in causing rotational motion the centripetal force does no work...but now we are talking about a tether ball with its radius decreasing because of each rotation...the force which pulls this tether ball inwards is the centripetal force...there is this change in displacement in...
I have proven that the energy has not increased...ofcourse the sting does work because the centripetal force is acting inwards and the ball is pulled inwards...how does that mean that the string does no work?...
centripetal force does no work in rotating the ball...but since the ball is being...
I am very late...but i think that it is pretty simple...angular momentum is conserved in the tetherball system...there is no net torque...
mVR=mvr.
V = vr/R
say at R = r/2
=> V = 2v.
I think the problem u say is in the conservation of energy.
Initial Kinetic energy =Ki= (1/2)m*v^2
Final...