Here radius of the circular turn r=10mr=10m
Speed of the car during turn v=36"km/hr"=(36xx10^3m)/(3600s)=10m/sv=36km/hr=36×103m3600s=10ms
Let m m represents mass of the bob of the pendulum suspended from the ceiling of the car then the magnitude of pseudo force acting on the bob will be same as the centripetal force on it during its motion in a circular path of radius r r with speed vv
During dynamic equilibrium let T T be the tension on string and thetaθ be the angle made by the string with the vertical.
TsinthetaTsinθ will balance the weight of the bob mgmg and TcosthetaTcosθ will be equal to centripetal force (mv^2)/rmv2r
So Tsintheta=mg.......[1]
where g -> "acceleration due to gravity"=9.8m/s^2
Tcostheta=(mv^2)/r.........[2]
Dividing [1] by [2] we get
tantheta=(rg)/v^2=(10xx9.8)/10^2=0.98
=>theta=tan^-1(0.98)=44.42^@