A block of mass M hangs from a rubber cord. The block is supported so that the cord is not stretched. The unstretched length of the cord is L0 and its mass is m, much less than M. The "spring constant" for the cord is k. The block is released and stops at the lowest point. (Use L_0 for L0, M, g, and k as necessary.)

Question

A block of mass M hangs from a rubber cord. The block is supported so that the cord is not stretched. The unstretched length of the cord is L0 and its mass is m, much less than M. The "spring constant" for the cord is k. The block is released and stops at the lowest point. (Use L_0 for L0, M, g, and k as necessary.)
(a) Determine the tension in the cord when the block is at this lowest point. 
1

(b) What is the length of the cord in this "stretched" position?
2

(c) Find the speed of a transverse wave in the cord, if the block is held in this lowest position.

drwls · Answer

(a) At the lowest point (if motionless), the cord tension equals the weight, M g.

(b) The stretched lendth of the cord is L = L0[1 + (Mg/k)] , since it stretches by an amount L0*(Weight)/k

(c) V = sqrt[Mg/(m/L)] = sqrt(LMg/m)

caroline · Answer

this is wrong

Keith · Answer

What is the right answer? Do you know?

caroline · Answer

T=2*M*g I can't get the other parts.

caroline · Answer

can you get the answers to b and c?