Question

Two blocks of masses m and M are connected by means of a metal wire of cross-sectional area A passing over a frictionless fixed pully as shown in the figure. The system is then released. If M = 2m, then the stress produced in the wire is ______.

Options

• 2mg/3A

• 4mg/3A

• mg/A

• 3mg/4A

Answer 1

Two blocks of masses m and M are connected by means of a metal wire of cross-sectional area A passing over a frictionless fixed pully as shown in the figure. The system is then released. If M = 2m, then the stress produced in the wire is 4mg/3A.

Explanation:

Tension in the wire, T ≈ `(2"mM")/("m"+"M")`g

Stress = `"Force/Tension"/"Area"=(2"mM")/("A"("m"+"M")`g

= `(2("m"xx2"m"))/("A"("m"+2"m"))` (M = 2m given)

= `(4"m"^2)/(3"mA")`g

= `(4"mg")/(3"A")`