# For angular simple harmonic motion or physical pendulum torque is calculated about which point or line.( in reference to hc verma part 1 chapter 12 question 26)

aku -- kumar
38 Points
13 years ago

in this kind of problems consider oscillation of centre of mass only that will make ur problem easier to solve

let the pendulum be at some Φ angle with vertical axis,  draw f.b.d ur self,

balance the driving force with mg,i.e; F=mg sinΦ

so a= F/m=g sinΦ if Φis very small then sinΦ ≈ Φ,

a = gΦ =g(x/l)     » a  proportional to x

then use time period formulae, t=2∏ √x/a .

Aravind Pazhayam
14 Points
13 years ago

In a physical pendulum the pendulum is hinged about a point and it rotates about that point.........however in this case this point cant be CM ...so the torque has to be take about a point where it does not pass through the line of action......in case of a mathematical pendulum it moves about the pivoted point.................for deep concepts refer RESNICK AND HALLIDAY......pardon me if in any way im wrong.....