Calculate the tensile stress anpplied at maximum load

[ashicus]

(a) The steel cable to the hoist is 15m in length and has a diameter of 25mm. Its steel has a maximum permissible working stress of 200N/mm2 and a Young’s modulus of elasticity of 210,000N/mm2. The maximum load allowed on the hoist is 75kN. Determine the following:-
(i) the cross-sectional area of the cable
(ii) the tensile stress applied to the cable at maximum
load
(iii) whether the tensile stress is within permissible limits
(iv) the strain on the cable at maximum load
(v) the extension of the cable at maximum load.


Ive worked out the cross sectional area with the pie R2 rule but halved the 25mm to get the radius.

the exact answer that i got was pie X 12.5^2 = 490.8738521234052

i can't seem to find anywhere how to work out parts 2,3,4 or 5

can somebody help me please

Thanks

Ash

 

[greentlc]

Part one is right although 5 significant figures is enough for this calculation. Are you currently taking a mechanics of materials course? Are you familiar with the equation:

$$\sigma = \frac{F}{A}$$

If so, how do you think it applies to part 2?