Sudheesh Singanamalla
Last Activity: 13 Years ago
The Question says that initially the chain was hanging from the table to the ground which means that initially N(normal force)=mg .......... Now mass of length l of the chain is m.
so mass of 1 unit length of the chain will be m/l
so mass of elemental part is m/l * dx
no when we pull the chain back to the table it goes up by a distance 'x' onto the table,
length of chain on the table is also 'x'
so the normal force is m*g
because it is on the table the normal force on every point is the same i.e mg
dx part is pulled up at a particular rate
so N = m/l*g * dx
integrating from 0 to x we get
N = m/l*g * ∫dx
N = mgx / l
work done is N*g
Work is mg2x/ l
my apologies if the answer is incorrect but this is the procedure . If i have made some calculation error please excuse.
Best Of luck
Please approve !