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donjt81

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**First part of the question:**

A high speed lifting mechanism supportsa 711kg object with a steel cable 24.9m long and 3.83cm(squared) in cross sectional area. Determine elongation of the cable.

I think I got this first part right... can anyone confirm my approach.

**stress = F/A**

F = mg = 711*9.8

A = .0383

strain = stress/Y

and then

elongation delta L = Lo * strain

Is this how you find elongation?

**Second part of the question**

By what additional amount does the cable increase in length if the object is accelerated upward at a rate of 3.3m/s2?

This was my approach to the second part. not sure if this is correct...

**stress = F/A**

but this time F = ma - mg (is this correct?)

everything else will be the same as the first part.

can someone please verify both these please.

Thanks in advance