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**1. The problem statement, all variables and given/known data**

the question is about a very flexible strain falling on a rigid table and ask for expression of normal reaction of table at a certain instant

**2. Relevant equations**

when i was trying to solve problem , i resolve N(normal reaction) into N1, N2

which N2 is the weight of chain already on table and N1 is the force by table to stop the chain(i consider it force to stop a small part of chain)

**3. The attempt at a solution**

then i use newtons 2nd law to find N2

N2 = v*dm/dt + m*dv/dt ( v for speed of chain just before touch the table)

i can find v*dm/dt = p*v^2 (p -linear density)

but when i tried to find m*dv/dt ,

i was confused about how to find the acceleration of that small part of chain with dt cannot be found

can anyone help me in correcting my calculation/concept?