Question

A 25mm square cross-section bar of length 300mm carries an axial compressive

load of 50kN. Determine the stress set up in the bar and its change of length when the

load is applied. For the bar material E = 200 GN/m
^2​

Answer 1

The correct answer is "299.88 mm".

Step-by-step explanation:

The given values are:

Length,

`l_o=300 \ mm`

Load,

`P=50 \ kN`

i.e.,

`=50* 10^3 \ N`

`E=200 \ GN/m^2`

`=2* 10^5 \ M/mm^2`

Now,

Stress,

⇒
`\sigma=(P)/(A)`

On substituting the values, we get

⇒
`=(50* 10^3)/(25* 25)`

⇒
`=80 \ N/mm^2`

The change in length will be:

⇒
`\Delta l=(Pl)/(AE)`

On substituting the values, we get

⇒
`=(50* 10^3* 300)/(25* 25* 2* 10^5)`

⇒
`=(15000* 10^3)/(1250* 10^5)`

⇒
`=0.12 \ mm`

hence,

⇒
`L=l_o-\Delta l`

`=300-0.12`

`=299.88 \ mm`