Two circular rods, one steel and the other copper, are both 0.780 m long and 1.50 cm in diameter. Each is subjected to a force with magnitude 4350 N that compresses the rod. What is the difference in the length of the two rods when compressed?

Respuesta :

Answer:

The difference in the length of the two rods when compressed is [tex]5.4\times10^{-5}\ m[/tex].

Explanation:

Given that,

Length = 0.780 m

Diameter = 1.50 cm

Force = 4350 N

(a). For steel rod

We know ,

The young modulus for steel rod

[tex]Y=2\times10^{11}[/tex]

Using formula of young modulus

[tex]e_{s}=\dfrac{Fl}{AY}[/tex]

[tex]e_{s}=\dfrac{4350\times0.780}{3.14\times(0.75\times10^{-2})^2\times2\times10^{11}}[/tex]

[tex]e_{s}=9.6\times10^{-5}\ m[/tex]

(b). For copper rod

We know ,

The young modulus for steel rod

[tex]Y=1.1\times10^{11}[/tex]

Using formula of young modulus

[tex]e_{c}=\dfrac{Fl}{AY}[/tex]

[tex]e_{c}=\dfrac{4350\times0.780}{3.14\times(0.75\times10^{-2})^2\times1.1\times10^{11}}[/tex]

[tex]e_{c}=1.5\times10^{-4}\ m[/tex]

The difference in the length of the two rods when compressed is

[tex]difference\ in\ length=e_{c}-e_{s}[/tex]

[tex]difference\ in\ length=1.5\times10^{-4}-9.6\times10^{-5}[/tex]

[tex]difference\ in\ length =5.4\times10^{-5}\ m[/tex]

Hence, The difference in the length of the two rods when compressed is [tex]5.4\times10^{-5}\ m[/tex].