A heavy particle is attached to one end of a string 1m long whose other end is fixed at O. It is projected from its lowest position horizontally with a velocity V:

−mgl(1−cos⁡θ)=12mv2−12mu2    .......(i)T−mgcos⁡θ=mv2l                      ........(ii)V2=gl(2−3cos⁡θ) (a) θ=π,V2=5gl, hence true  (b) 3.5=2−3cos⁡θ,cos⁡θ=−12       ⇒A=120∘ hence true  (c) 2=2−3cos⁡θ,cos⁡θ=0,θ⇒π2, hence true  (d) 1=2−3cos⁡θ,cos⁡θ=13,θ>60∘, hence true