- #1

Saitama

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## Homework Statement

The end of a chain of length L and mass per unit length ρ, which is piled up on a horizontal platform is lifted vertically with a constant velocity u by a variable force F. Find F as a function of height x of the end above platform.

A)ρ(gx+2u^2)

B)ρ(gx+u^2)

C)ρ(2gx+ρu^2)

D)ρ(u^2-gx)

## Homework Equations

## The Attempt at a Solution

The chain goes up with a constant speed so at any instant the net force should be zero i.e. F=mg. If the height of the end is x, then m=ρx therefore F=ρgx. But there is no such option.

Any help is appreciated. Thanks!

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