A string breaks under a load of 4.8kg A mass of 0.5 kg is attached to one end of a string 2 m long and is rotated in a horizontal circle . Calculate the greatest number of revolutions that the mass can make without breaking the string .

Explanation

Given, `m=0.5kg, r=2m, g=9.8ms^(-2)`
The maximum tension that the string can withstand,
`F=4.8" kg-wt"=(4.8xx9.8)N`
Let the maximum number of revolutions per second be n
`because" "F=mromega^(2)=mr(2pin)^(2)`
`rArr" "n^(2)=(F)/(4pi^(2)mr)=(9.8xx4.8)/(4xx(3.14)^(2)xx0.5xx2)=1.215`
`rArr" "n=sqrt(1.215)=1.102rps`
`rArr" "n=1.102xx60=66.13rps`