http://www.freeimagehosting.net/uploads/th.67869d8231.gif a disk with radius R and mass M is sticked on axle that goes threw the center of the table. between the disk and the table there is no friction. on the big disk there is a smaller disk without mass with radius r and a weight less rope is wrapped around it. this rope is connected to a spring with elastic constant K . the springs other end is connected to a wall. we assume that the system is at equilibrium . and we throw a mass m on the big disk with velocity [tex]V_0[/tex] and it hits her in point A on angle [tex]\alpha[/tex] the collision is absolutely elastic and mass m sticks to the disk. because of the collision the system start to do harmonic movement. and particularly angle[tex]\Theta[/tex] describes the position of point A of the disk. point A also moves harmonically [tex]\Theta=\Theta_0\cos(\omega t+\beta )[/tex] calculate the amplitude of [tex]\Theta_0[/tex] ?? this is a question from hell i get the impression that the spring is moving from right to left and from top to bottom. usually i put forces and from them i calculate what i need . but here i dont know from what place to start from what equations to start and how to proceed ?? if i start from the collision? with respect to what point do i need to calculate angular momentum(rmv) equations?? i cant understand why in the solution they say that the amplitude of the spring A is A=R[tex]\Theta_0[/tex] ??