Two blocks of masses `1 kg` and `2 kg` are connected by a metal wire going over a smooth pulley as shown in figure.
The breaking stress of the metal is `(40//3pi)xx10^(6)N//m^(2)`. If `g=10ms^(-2)`, then what should be the minimum radius of the wire used if it is not to break?

Options

A. 0.5 mm
B. 1 mm
C. 1.5 mm
D. 2 mm

Answer

B

Explanation

(c) Breaking stress `=(F)/(A)=(40)/(3pi)xx10^(6)Nm^(-2)`
According to question,
`(40)/(3pi)xx10^(6)=(3xx10)/(pir^(2))`
`r^(2)=(9)/(4xx10^(6))`
`r=1.5xx10^(-3) m =1.5 mm`