A semicircular wire hs a length L and mass M. A paricle of mass m is placed at the centre of the circle. Find the gravitational attraction on the particle due to the wire.

Answer

B

Explanation

`L = pi R`
`:. R = (L)/(pi) rArr F = int_(0)^(pi) dF sin theta`
`= int_(0)^(pi) (GdM.m)/(R^(2)) sin theta`

`= int_(0)^(pi) (G((M)/(pi)d theta))/(L^(2)) (pi^(2)) sin theta`
`= (2 piG mM)/(L^(2))`